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Digitized by the Internet Archive 
in 2011 with funding from 
The Library of Congress 



http://www.archive.org/details/leathermanufactuOOschu 



THE 



LEATHER MANUFACTURE 



IS THE 



UNITED STATES 



A DISSERTATION ON THE METHODS AND 
ECONOMIES OF TANNING. 



/ 
BY JACKSON S. SCHULTZ. 



H 



WITH NUMEROUS ILLUSTRATIONS, 



TO WHICH IS ADDED A REPORT ON THE RELATIVE ECONOMIES OF 
BURNING WET SPENT TAN, BY THERON SKEEL, C. E. 



NEW YORK: 

" SHOE AND LEATHER REPORTER " OFFICE, 

1870. 




J*» 



CONTENTS. 



Page. 
Introduction, ----.... xm 

CHAPTEE I. 

SELECTION AND CLASSIFICATION OF HIDES AND 

SKINS. 

SIMILARITY OF STOCK AS TO WEIGHT, SUBSTANCE AND CONDITION, 

HIGHLY IMPORTANT ASSORTING IN THE SOAK AND HD3E MILL 

HIDES SHOULD BE OF EQUAL CONDITION ON ENTERING THE HAND- 
LERS—BREAKING THE NERVE IN CALF, KIP AND UPPER LEATHER 

IMPOLICY OF WORKING SEVERAL KINDS OF HIDES IN ONE YARD 

AT THE SAME TIME. -------_ \<J 

CHAPTEE II. 
PREPARATION OF HIDES FOR THE BARK— SWEATING. 

COLD AND WARM SWEATING CONSTRUCTION OF SWEAT PITS — CLEAN- 
LINESS, LIGHT AND IMPENETRABILITY TO AIR NECESSARY IN COLD 

SWEAT PITS PROPER CONDITION OF STOCK BEFORE ENTERING THE 

PITS CARE NECESSARY IN THE SWEATING PROCESS TREATMENT 

AFTER THE HIDES COME FROM THE PITS PART LIMING AND PART 

SWEATING GREASE AND SALT ON HIDES. - - - - 23 

CHAPTER III. 
PREPARATION OF HIDES FOR THE BARK— LIMING. 

GETTING READY THE LIMES THEIR AGE AND STRENGTH EFFECT OF 

THE LIME ON THE FLBER PLUMPING AND BATING PROF. LUF- 

KIN'S PROCESS — THE " BUFFALO" METHOD THEIR RESULTS 

HANDLING IN THE LIMES. -------31 



Y2 CONTENTS. 

CHAPTER IV. 
PREPARATION OF HIDES FOR THE BARK— FLESHING 

AND TRIMMING. 

THE BEAM WORK CLOSE FLESHING, WITHOUT BREAKING THE GLUE 

CELLS— FLESHING LIME SLAUGHTER STOCK WORK TO BE DONE 

BEFORE LIMING — FLESHING SWEAT STOCK IT SHOULD BE DONE 

WITH A WORKER THE GERMAN FLESHER TRIMMING CROP 

LEATHER AND BACKS ADVANTAGES OF TRIMMING UPPER AS 

WELL AS SOLE — "ROUNDING " TRIMMING BEFORE TANNING 

BEST METHOD OF UTILIZING THE HEAD, PATE, ETC. - 33 

CHAPTEE V. 
GRINDING BARK— BARK MILLS. 

THE [NEXPENSTVE AND ABUNDANT POWER OF SOLE LEATHER TANNERIES 
— GRINDING BARK FINE AND UNIFORM USEFULNESS OF SCREEN- 
ING THE GROUND BARK THE DOUBLE-GRINDING MILL ITS 

EFFECTIVENESS WITH DAMP BARK THE ALLENTOWN MULL 

ADVANTAGE OF A STRONG MILL AND A WEAK COUPLER THE SAW 

CUTTING MILL A BARK CRUSHING MACHFNE— THE PROPER SPEED 

AT WHICH MILLS SHOULD BE RUN TANNIN LEFT IN THE BARK. - 4G 

CHAPTER VI. 
LEACHING. 

; N VS. RESINOUS AND COLORING MATTER TANNIN REQUIRED TO 

U \ KE GOOD WEIGHT EXTREME HEAT IN LEACHING INJURIOUS 

- >PING THE BARK THE PRESS LEACH — HEAT TO BE APPLIED 

ONLY TO THE WEAKEST LEACH CONSTRUCTION OF LEACHES 

<!.\V AND LOAM PACKING FOR THE SEDES AND BOTTOMS WORK- 
ING THE PR I 1 1— THE SPRINKLER LEACH REVOLVING DE- 

TACHED LEACH. -------.55 

CHAPTER VII. 
HANDLING. 

THE HAND REEL- THE ROCKER HANDLER ITS CONSTRUCTION AND 

OPERATION — IMMERSED I I; EM WHEELS A METHOD OF RAISING 

HIDES PROM THE HANDLER VATS — THE TUB WHEEL HANDLER 

HANGING HIDE8 IN THE HANDLERS — TnE " ENGLAND " WHEEL 

HANDLING WITH THE COX ROLLERS. - G8 



CONTEXTS. VU 

CHAPTEE VIII. 
HANDLING AND PLUMPING. 

THE USE OF VEGETABLE AND MINERAL ACIDS THE EARLY USE VS" 

VITRIOL BY AMERICAN TANNERS CONSIDERATIONS AFFECTING THE 

AMOUNT WHICH MAY BE USED ITS EFFECT ON LIMED AND SWEAT 

STOCK STRENGTH AND AGE OF LIQUORS TO BE USED IN THE 

HANDLERS DIFFERENCES IN THE HANDLING AND PLUMPING OF 

SOLE AND UPPER LEATHER. ------ 76 

CHAPTEE IX. 
LAYING AWAY. 

TIME EEQUIRED AND STRENGTH OF LIQUOR WHICH SHOULD BE 

EMPLOYED TANNING IN THE HANDLERS VS. LAYING AWAY 

EUROPEAN METHODS " BLACK ROT " AND WHITE SPOTS THEIR 

CAUSES AND THE REMEDIES SHOULD HIDES BE LAID AWAY GRAIN 

UP OR FLESH UP ? MAKING WEIGHT IN THE LAST LAYER. - - 84 

CHAPTEE X. 
DKYING AND FINISHING. 

WASHING AND SCRUBBING THE LEATHER THE " HOWARD SCRUBBER " 

WHEEL OR DRUM SCRUBBING DRAINING! HOW THE ADMISSION 

OF LIGHT AND AIR SHOULD BE REGULATED IN DRYING DAMPENING 

BEFORE ROLLING THE FIRST AND SECOND ROLLING — EFFECT OF 

THE ROLLING ON THE BUFFING QUALITIES BLEACHING WITH 

SUGAR OF LEAD AND SULPHURIC ACID THE WARM SUMAC BATH 

EFFECT OF THE LATTER ON CALFSKINS, GRAIN LEATHER, ETC. - 94 

CHAPTEE XI. 

THE CAUSES WHICH AFFECT COLOR AND ASSIST IN 

THE MAKING OF A VALUABLE EMBOSSING GRAIN; 

WHY LEATHER SHOULD BE THOROUGHLY DRIED STRUCTURE OF THE 

GRAIN IMPORTANCE OF A PERFECT FINISH CARE TO BE TAKEN 

TO AVOID STAINS AND DISCOLORATION " CUIR " COLOR — THE 

NATURAL HEMLOCK COLOR " RUSSIA LEATHER " COLOR — FRAUDS 



IN SELLING HEMLOCK FOR OAK LEATHER DURING THE WAR COL- 
ORING TO BE DONE IN THE HANDLERS EFFECT OF " STRIKING " 

THE GRAIN. - - - - - - 103 



CONTENTS. 
V1U 

CHAPTER XII. 
CONSTBUOTOK OF TAMffiEffiS-THE TTJBEET DHffiB. 

„ ass.0* «i— a"™-™"^"™™ 

DRIEE _ ro CAPABU-mES FOB BBYIKC, EE.THEK B. QB.CKEB 
i „„,-T K »» THE WEATHEE-™ CONSTBUCnON 

„„„ „ caeaote BBOEU.BE eeoeoethoneb TO that 
.,,„, rABD _H0* ABB WHEB HEAT SHOEEO EE ESEO-HOW TO 
,,„:„ „ 1 ,,v„„ a ,Vn„B „E THE EEATHEB-.AV.BO OE EAEOE O, ^ 
THE IUBEET DRYER. 

CHAPTEE XIII. 
CONSTRUCTION OF TANNERIES-PLANS, FOUNDA- 
TIONS, ETC. 

rH0K0UGH EXAMINATION OF PRESENT STRUCTURES AND APPLIANCES 
W1V ,SW:,E BEFORE BUILDING-IMPORTANT CHANGES FROM THE 
PRESEN T GENERAL USE OE STEAM INSTEAD OE WATER POWER- 
L0CATING ON "MANUFACTURING" AND ."CULINARY" STREAMS- 
A L OAM CLAY, OR SANDY FOUNDATION— FILLING IN BETWEEN 
VATS ,ND LEACHES WITH LOAM OR CLAY-PLACING THE VATS— 
,,„, "BUFFALO" vat- -BOX- VATS- THE PROCESS OF "PUD- 
M1N(; - , N SETTING THK VATS— UPPER CONDUCTORS— SIDE AND 

END WA1 LS. 

CHAPTER XIV. 
CONSTRUCTION OF TANNERIES— LEACHES. 

, n„ OE SQUARE LEA. BES— THE DURATION OF LEACHES ABOVE AND 

8I TNK IX THE I ROUND— HOW TO BUILD A ROUND LEACH— HOW TO 

MAKE \M> SET LEACHES EN THK GROUND— THE CAPACITY OF THE 

LEACHES TO BE PROPORTIONED TO THE SIZE OF THE TAN- 

- 12G 

M BY. 

( UAPTEPv XV. 

CONSTRUCTION OF TANNERIES— FRAME WORK AND 

LOCATION OF BUILDINGS. 

WHY Till V SHOULD BE 0NL1 ONE-STORY HIGH FOR THE YARD AND BEAM 

,,,„.! aA\ NG in INSURANCE BY SEPARATING THE BUILDINGS— 

, u . , ,, Mill R TO THE "TURRET " DRYER— TRANSMITTING 



CONTENTS. 



IX 



> 



POWER TO DISTANT BUILDINGS— PROPER SPEED FOR BARK MILLS 
AND ELEVATORS— SIMPLE PROVISIONS AGAINST EIRE AND BREAK- 
AGE, AND TO PREVENT DUST. - . _ .134 

CHAPTER XVI. 

THE ROSSING OF BARK. 

THEORIES OF THOSE WHO ADVOCATE ROSSING— ITS COST— DIFFICULT* 
OF ROSSING WITHOUT TOO GREAT LOSS OF TANNIN— STRENGTH 
OF LIQUORS WHICH MAY BE OBTAINED FROM ROSSED AND UN- 
BOSSED BARK— POSSIBLE ADVANTAGE IN ROSSING BARK FOR EX- 
PORT LN THE " LEAF." - -.A-, 

- Ml 

CHAPTER XVII. 
UTILIZATION OF TANNERY REFUSE. 

BURNING THE WET TAN— GLUE STOCK— IMPORTANCE OF KEEPING THE 

PIECES PURE AND SWEET— PRESERVING, CLEANSING AND DRYING 

THEM— USES FOR CATTLE HAIR— THAT WHICH COMES FROM SWEAT 

. OR LIMED STOCK— WASHING, DRYING AND PACKING— FERTILIZING 

LIQUIDS FROM THE LIMES AND SOAKS. - 1 A n 

CHAPTER XVIII. 
TANNING MATERIALS. 

DIFFERENT KINDS OF HEMLOCK BARK— INFLUENCE OF SOIL AND CLI- 
MATE ON THE QUALITY— HEAVY AND LIGHT BARK— VARIETIES OF 
OAK BARK— THE "SECOND GROWTH" BETTER THAN THE FIRST— 
GAMBIER— ITS GROWTH AND PREPARATION FOR MARKET— ITS 
COST COMPARED WITH THAT OF BARK— VALONIA, DIVIDIVI, MYRA- 
BOLAMS " SWEET FERN," ETC. - i _ ]rr 

CHAPTER XIX. 
THE COST OF TANNING. 

THE SEVERAL ITEMS VARYING WITH DIFFERENT TANNERS— DIFFERENCES 
FROM UNEQUAL WEIGHT OF THE CORD OF BARK— THE AMOUNT 
OF TANNIN IN UPPER LEATHER AS COMPARED WITH THAT IN SOLE 
LEATHER— COMPARATIVE COST IN MAKING HEAVY AND LIGHT 
GAINS— THE THEORETICAL STRENGTH OF BARK NEVER REALIZED 
—COST OF "UNION" AND OAK TANNING— ESTIMATED COST OF 

TANNING IN EUROPE. - - „„ 

- J Oil 



176 



x cc:;tl:;ts. 

CHAPTER XX. 
QUICK TANNING PROCESSES. 

•ION ERRORS OF THOSE OUTSIDE OF THE TRADE — HOW WORTHLESS 
PATENTS ARE MULTIPLIED — EXPERIMENT IN TANNING BY HYDRO- 
STATIC PRESSURE VACUUM TANNING — DIFFICULTIES ATTENDLNG 

'111 IS METHOD HOW AGITATION OF THE FIBER FACILITATES THE 

PROCESS A GENTLE MOVEMENT, WITH OCCASIONAL REST, MOST 

M FICACIOUS TANNING VS. TAWING. - 

CHAPTER XXI. 

THE SPECIES AND GROWTH OF HIDES. 

" HEALTHY" AND "WELL GROWN " HIDES — DIFFERENCES IN HIDES AT 

VARIOUS SEASONS OF THE YEAR EFFECT OF CLIMATE AND FOOD 

( >N TKXTURE AND GROWTH IMPROVED BREEDS OF CATTLE MAKE 

HIDES THEN AND SPEEADY COLD CLIMATE MAKES A COARSE FIBER 

AND WARM CLFMATE A FINE TEXTURE EAST INDIAN, AFRICAN 

AND SOUTH AMERICAN HIDES THE HIDES FROM THE EASTERN 

AND MIDDLE STATES AS COMPARED WITH THOSE FROM .THE WEST- 
ERN PRAIRIES — CARE TAKEN OF CATTLE IN EUROPE. - - 1SS 

CHAPTER XXII. 
FRENCH AND GERMAN CALF AND KB?. 

WHERE OCR IMPORTED STOCK COMES FROM— CAREFUL ASSORTING OF 
Tin: RAW smi K to INSURE UNIFORMITY IN WEIGHT, SUBSTANCE 

AND GENERAL CONDITION SOAKING AND MILLING BREAKING 

THE NERVE — LIMING BATING AND WORKING OUT LTME — COLOR- 
ING LND HANDLING LAYING AWAY AFTER WORKING STUFFING 

— DRYING — SLICKER WHITENING BLACKING AFTER THE STOCK 

18 CUT OUT C8TJAL IN EUROPE — VEGETABLE OILS USED INSTEAD 
OF FISH OILS — DEFECTS IN FOREIGN CALFSKINS— STEADY IM- 
PROY1M1NT IN AMERICAN CALFSKINS. - 294 

CHAPTER XXIII. 
GRAIN AND BUFF LEATHER. 

UNO MACHINES MAKING SPLIT LEATHERS FROM GREEN HIDES 

IB FROM TANNED LEATHER — EVERY KIND OF NATURAL GRAIN 

BUCCESSFII 1 V IMITATED — STRENGTH AND DURABILITY OF SPLIT 



CONTENTS. XI 

LEATHERS THEIR INTRODUCTION TO EUROPEAN CONSUMERS — ES 

SENTIALS TO BE CONSIDERED IN THE MANUFACTURE OE GRAIN 
AND BUFE LEATHER. _____ 210 

CHAPTER XXIY. 
CURRYING AND FINISHING. 

THE STUFFING WHEEL AND HOW TO USE IT TO PURIFY AND CLEANSE 

DIRTY GREASE HOW TO MAKE STUFFING FLESH BLACKING 

FLOUR AND SIZE PASTES — HARM THAT MAY BE DONE BY DEPEND- 
ENCE UPON RECIPES DAMPENING LEATHER BEFORE AND AFTER 

APPLYLNG OIL AND TALLOW. - - - - -218 

CHAPTER XXV. 

DIRECTIONS FOR THE CONSTRUCTION OF DETACHED FURNACES FOR 

BURNING WET SPENT TAN, BY THERON SKEEL, C. E. - - - 224 



LIST OF ILLUSTRATIONS. 

Page. 
I !( >ld Sweat Pits, --------- 249 

1 1 mi: Mux, - 251 

Band Reel, 253 

Rocker Handler, - - - - . - - - 255 

Sole Leather Roller, -------- 257 

Turret Dryer, - - - - - - - - - 259 

Sprinkler Leach, - - - 261 

Cutting Mill, -------- 263 

Allentown Bark Mill, ------- 265 

Howard Leather Washer, ------ 265 

S \ i .km Tan Press, - - - - - - -.- - 267 

Loi kwood Leather Scourer, - 269 

Fitzhenry Leather Scourer, - ------ 271 

Burdon Leather Scourer, ------- 273 

Si i FFENG WHEEL, --- - 275 

Charles Korn's Wbttener, - - - -■ - 277 

Union Whitener and Buffing Machine, - -279 

I ' Whitener and Buffing Machine, - 281 

Unioh I -i mhi i: Splitter, ------- 283 

Henry Lampert'b Hide Worker, - 283 

Outline and Trim of Hdde, ------ -285 

Tanners' hnd Curriers' Tools, ------ 287 

II. ,r Furnace \t Wilcox V\ nn., Plates I, II, HI, - 289, 291, 293 
Desigv fob WetTak Furnace, Plates I\ t , V, VI, - 295,297,299 



INTRODUCTION. 



This Centennial year seems an appropriate periol in which 
to review the progress and present attainment of the tanners 
art m America. In the chapters which are to follow it is 
not proposed to give a chronological history so much as the 
general progress of the trade, and even that progress will be 
considered in subordination to the permanent advance- 
ment of the whole manufacture, rather than to the glorifica- 
tion of any special period of our trade history, or the com- 
m3ndation of any particular man or class of men, however 
conspicuous they may have been daring critical periods. 
This purpose will mike it unnecessary to inquire whether 
" Simon " was a good or poor tanner ; indeed, whether he 
was a tanner at all, since, whatever his merits as an artisan, 
they have long since been surpassed by others with far 
better methods. 

For similar reasons no attempt will be made to bring un- 
der review the various exploded patents and so-called im- 
provements that have for the past fifty years been pressed 
on the attention of tanners. No volume, however large, 
would be adequate to contain the recital of their origin and 
pretensions. But so many of such improvements as have 
been at any time adopted by any considerable number of the 
trade — and particularly if they have a practical existence in 



xiv INTRODUCTION. 

any of our modern yards — will receive respectful considera- 
tion. This, to be useful, must be candid, and free from ail 
bias. 

To intelligently contrast the merits of mechanical inven- 
tions — to hold an even hand in weighing the advantages and 
disadvantages of systems and methods which include among 
their advocates men equally intelligent — is a task not likely 
to be accomplished without involving the writer in much cen- 
sorious criticism. But if an entire absence of all ownership 
or interest in patented or other improvements can qualify 
one for the task, then these chapters will contain a fair 
presentation of the merits of all claims. 

The form chosen in which to present this subject is inten led 
to elicit honest inquiry and full discussion. Instead of a treatise 
giving in dogmatic language the processes which it is claimed 
tanners have adopted or must adopt, it is intended here to pre- 
sent the merits and defects of known systems and methods as 
their advocates would state them, and hold these up in contrast 
with other methods commended by equally intelligent men, 
and thus, by candid comparison, show their relative merits, 
and indicate such preference as may appear to be justified by 
our experience. This course of inquiry and presentation 
will, it is believed, lead to far better results than if precon- 
ceived and fixed theories and opinions were enunciated and 
defended. In still other words, these chapters will contain 
a toleraari discussion of the present condition of the tanner's 
art in America, and, by way of contrast and honorable emu- 
lation, with the relative position of the same trade in the 
more advanced nations of Europe, and in the treatment of 
these subjects there will be no pedantic use of terms, either 
amcaJ or otherwise; only such phrases and words will 
be employed as are familiar to all practical tanners. 

\\ bile it is conceded that the tanner's art is largely chemical 



INTRODUCTION. XV 

iv its nature, and may in the future be greatly advanced by 
the study and application of chemical laws, in this prelimi- 
nary inquiry it is thought expedient for both writer and 
reader to confine attention to the tanner's art as understood 
by ordinary workmen. 

It is proposed here to treat only of the subject of "tan- 
ning" as contradistinguished from "tawing." The art of 
" tanning " differs so widely from that of " tawing " that an 
expert in the one may be a novice in the other. They do not 
assimilate any more than the glove maker does with the boot 
or shoe maker. The latter uses " tanned," while the former 
uses " tawed " leather. Sir Humphrey Davy has drawn the 
distinction by the adoption of a chemical formula and test. 
He says, in substance, that leather is a chemical combination 
of gelatine and tannin, its characteristic being that, when 
combined, water will not separate the constituents or dissolve 
the connection ; whereas, in the tawing process, water will 
separate them and return the gelatine and salt or alum into 
their original elements. 

In America we have but little experience with any other 
than bark tannage, and, therefore, if we speak at all of the 
various substitutes for bark used by tanners in the old world, 
it must be from a very limited experience and a qualified 
knowledge. In deference to the success of the tanners of 
Great Britain we are compelled to admit that vegetable sub- 
stances other than bark — such as cutch, terra japonica, valo- 
nia, myrabolams, divi divi, etc. — do tan leather. These ma- 
terials practically do the tanning for Great Britain, and make 
a serviceable and even artistic leather. The barks of our 
forests, particularly those of the hemlock and the oak, are, 
then, only two among the tanning agents which are to be em- 
ployed in making leather. But as these are the agents with 
which we are most familiar — indeed, the only agents in gen- 



xv i INTRODUCTION. 

oral use in this country— it is with reference to their use that 
these chapters will treat, considering only incidentally such 
other tanning materials as come into competition. 

The only exception to the use of barks or bark extracts in 
this country is that of " terra japonica," and this is used only 
to a limited extant. But as this tanning substance has been 
the innocent cause of much misapprehension, and has led 
many novices into grave mistakes, as we pass along we may 
turn aside occasionally to point out this rock on which many 
hopes and even fortunes have been wrecked. 

In illustrating the machinery which is most approved by 
tanners and workers in leather.it must be understood that only 
such kinds are here presented as are new, or comparatively so, 
in construction. Many useful machines are now in use, but 
so old and familiar that it is not thought expedient to en- 
cumber these pages with their presentation.. Some of the 
illustrations are of old machines with new attachments; 
whenever this occurs an attempt will be made to designate 
the added novelty, in the text accompanying the drawing, or 
in the drawing itself. 



CHAPTER I. 

SELECTION AND CLASSIFICATION OF HIDES AND 

SKINS. 

SIMILARITY OF STOCK AS TO WEIGHT, SUBSTANCE AND CONDITION, HIGHLY 

IMPORTANT ASSORTING IN THE SOAK AND HIDE MILL HIDES SHOULD 

BE OF EQUAL CONDITION ON ENTERING THE HANDLERS — BREAKING THE 

NERVE IN CALF, KD? AND UPPER LEATHER IMPOLICY OF WORKING 

SEVERAL KINDS OF HIDES IN ONE YARD AT THE SAME TIME. 

To secure the best results throughout the tanning and fin- 
ishing of leather, there must be equality of condition, and the 
conditions must be favorable ; among these conditions are 
similarity or equality of stock at the start. Dry flint hides 
cannot be worked with salted; heavy hides cannot be 
brought into condition with light ones in the same pack. 
As far as possible, then, both as to weight, substance and 
condition, the pack must be in all its respects equal. Some 
tanners think they effect the same result by assorting then- 
packs after soaking, or after milling or sweating ; but, exer- 
cising all the judgment that is possible from the outset, there 
will be opportunity to reject and assort in each stage of the 

process. 

Where it is possible the whole lot of hides should be clas- 
sified before any portion is put into the soaks. This is 
not always convenient or possible— as, for instance, where 
the hides are brought from a distant depot, sometimes many 
miles removed, on the return of teams from delivering loads of 
leather sent away. But where it is at all convenient the 



18 THE LEATHER MANUFACTURE. 

heavy hides should be selected and worked in first, enabling 
the whole lot to come out at the same time. This practice 
will be found far better than to assort the packs on the last 
layer, throwing the heavy sides back, and, aside from the 
consideration of being able to return the whole lot promptly 
and together, it enables the tanner to give the hides better 
and more considerate treatment in the soaks, mills and 
sweats. 

After classifying all hides of the same weight and general 
appearance it will be found that some soften much more 

idily than others. This difference will be discovered gen- 
erally in the first milling. The attendant, standing by the 
side of the mill constantly, with his hand on each side as it 
comes round in its turn, will " draw " (remove) the soft sides. 
This will leave the hard and unyielding sides in the mill 
until all the soft ones have been taken out. As a general 
experience it will be found inexpedient to " force " these re- 
maining sides. It is better that they be taken out and re- 
turned to the soak, and not remilled until a future period, 
depending on the weather and condition of the water. 
When the weather is very cold these hard sides may be 
treated to a bath of moderately warm water — say up to 
80 of heat — for a few hours. If they are sound they will 
usually yield on the second milling. 

The packs should not be formed to go into the sweats 
until after they have come from the mill. The experience 
gained in milling will enable every intelligent man to send 
into the sweats a given number of sides in nearly equal con- 
dition. Prom the entrance of the stock into the reception, 
or hide house, until it gets into the sweats, and, indeed, 
after it has come from the sweats, the object should be to 
equalize the sides in the same pack. 

Especial attention to properly softening is confined almost 



THE LEATHER MANUFACTURE. 19 

exclusively to the dry flint stock ; botli green and dry salted 
hides soften without effort, and yet it is important that the 
substance and condition should be the same in each pack, 
even in this description of hide. Pickled hides should be 
kept separate from salted, and green salted from freshly 
taken off hides. 

If it is important in sole leather hides to maintain uni- 
formity of condition in the beam house, it is much more so 
in upper leather hides, kip and calfskins. The writer does 
not hesitate to say that, in the absence of this equality of 
condition, upper, harness and calfskins cannot be carried 
through the tanning and finishing processes in a workman- 
like manner and with good results. 

This difficulty may be aptly illustrated by the experience 
of many small tanners, who cannot wait until they " take in 
enough stock " of any one description to make a pack ; they 
feel obliged to make up a pack of hides, kip and calf, some 
green, some fully dried, and some partially dried or dry 
salted. The result is that neither class is well worked or 
prepared ; as they had the misfortune of being joined in the 
beam house,, they go linked through the yard, and tho whole 
pack comes out a tanner's abortion. 

But even in cases where hides, kips and calfskins are 
worked separately in the same yard, the tanner oftsn thinks it 
quite sufficient if he works each class by itself, whereas there 
are as many conditions to be observed in each class of salted 
as in dry hides ; not, perhaps, in order to secure a sound re- 
sult, but much more is required of this class of stock. The 
grain must be fully preserved, and the whole fiber must be re- 
duced to a pulp — as it can be, when the nerve is thoroughly 
broken, and not before. This nerve depends upon many con- 
ditions for its tenacity. It is easiest broken when fresh from 
the animal, but may ba severed under any ordinary circum- 



20 THE LEATHER MANUFACTURE. 

stances. No calf, kip or upper leather can he made with those 
yielding qualities so highly appreciated in our country ivithout 
the severance of this nerve* and the sooner our tanners ap- 
preciate this fact the sooner will they make leather to take 
the place of the French and German calfskins that so largely 
supply our best custom boot and shoe makers at the present 
time. 

In all the processes, commencing with the soaking and mill- 
ing, or wheeling, through the lime and bate, each pelt must 
1 ie individually treated, and if the conditions are much varied, 
more judgment and care will be necessary in their treatment 
as a whole than if they are substantially alike. 

In the latter case ordinary intelligence would suffice to per- 
form creditable work ; this degree of intelligence is all 
that the employer has a right to expect, and hence the im- 
portance of making as light drafts upon the brain-power of 
his men as possible, by making the labor uniform on each 
piece of stock. 

w few calfskin tanners in this country think it import- 
ant to classify their skins ! Do they not work all skins from 
six pounds to twelve in the same pack ? Whatever is classed 
as " veal " goes together ; the first selection that is thought of 
is when the finishers are wanting stock ; the packs are then 



little is known in this country of the process of breaking the nerve, or even 

su.-h nerve, thai I venture to add this note, somewhat out of 

i in which this subject is treated. When a calf is first killed, this nerve 

v, ill be Been, bj Bervation, twitching and contracting on the flesh for a few 

rft< c .1. ath; the whole flesh appears alive with muscular action ; when 

I. this action will appear to he the result of innumerable interlacing 

trich a wise Providence has placet thereto expand or contract to meet 

quirements of the seasons and the varying condition of the animal. When 

'•' s '" ■'■ '' 'l"iet and fixed they hold the fiber of the skin, giving it a 

ing. To demonstrate the existence of this nerve let 

at be i ried : Take a green skin, throw it over the tanner's 

and, with a worker, put ten minutes' hard work on the flesh side of one-half 

nil will be that the half of the skin worked will be distended 

even pulpy. Much more would this be the effect if done after soaking 

> Bhould be before the usual beam work is done 



THE LEATHER MANUFACTURE. 21 

assorted and the tanned skins are selected out and sent to 
the currying shop, while the heavy ones are given another 
liquor; This is beginning at the wrong end ; the selection 
should have taken place before the skins entered the beam 
house, when the advantages of classification would have been 
secured all the way through the process. In a well regulated 
calf or kip skin yard, from the time the skins enter the tan- 
nery they are mated (for reasons hereafter to be stated), and 
continue this connection through the whole after tanning 
process. But how can dissimilar sizes and substances be suit- 
ably paired, and so placed, grain to grain, as to fully cover 
each other? 

What has been said thus far goes to the advantage of the 
intrinsic quality of the stock ; but suppose some hides or skins 
are damaged, or partially so ? Those should by no means 
be allowed to contaminate the good. They are the sick mem- 
bers, and must be placed in hospital, under observation ; they 
may not all have the same disease, and must be placed in dif- 
ferent "wards" or "apartments" for special treatment. 

When one thinks of the indiscriminate and forcing pro- 
cesses which valuable stock receives at the hands of many 
tanners, the inhumanity of the treatment is forced on one's 
mind. Sick or well, strong or weak, large or small, the same 
methods, the same trying ordeal, must be passed by all, and 
that so few should break and fail is the wonder. 

It remains only for me to say a word about the impolicy of 
working a variety of hides in the same yard. It is not to be 
denied that some tanners succeed in making good stock out 
of a variety of hides under treatment at the same time ; but 
this is the exception, and should not be ventured upon by the 
average tanner. At least one season's or one year's hides 
should be of one kind, or as nearly so as possible. Buenos 
Ayres, Montevideo and Bio Grande are sufficiently alike to 



22 THE LEATHER MANUFACTURE . 

be classed together ; Central American and Matamoras, and 
even dry Texas, are, possibly, similarly conditioned. Califor- 
nia and Western may well be treated as similar hides, requir- 
ing like treatment ; but there cannot safely be treated dry 
salted and dry flint hides in the same beam house ; lime and 
sweat stock cannot go through together without danger, or 
certainly with hope of the most satisfactory results. The 
best leather is made by tanners who work a uniform descrip- 
tion of hide. This is the usual experience, and is based on 
common sense. 



CHAPTEK II. 
PREPARATION OP HIDES FOR THE BARK— SWEATING. 

COLD AND WARM SWEATING CONSTRUCTION OF SWEAT PETS — CLEANLINESS, 

LIGHT AND IMPENETRABILITY TO AIR NECESSARY IN COLD SWEAT PITS 

PROPER CONDITION OE STOCK. BEFORE ENTERING THE PITS CARE NEC- 
ESSARY IN THE SWEATING PROCESS TREATMENT AFTER THE HIDES 

COME FROM THE PITS PART LIMING AND PART SWEATING GREASE 

AND SALT ON HIDES, 

In contradistinction to the sweating process of Southern 
Europe and Great Britain, the American method is called 
the " cold sweat "; theirs is denominated the " warrn sweat." 
In France, Germany, Austria and Switzerland, perhaps also 
in other countries of Continental Europe, the tanners sweat 
their green hides by piling one on top of the other, laid 
out flat, and covering them up with spent tan or horse ma- 
nure until decomposition begins. This is their process of pre- 
paring sole leather hides ; for upper they lime, substantially as 
we lime our upper stock. 

In this chapter both the construction and practical opera- 
tion of the sweat pits will be considered. The modifications 
and changes of construction in the form of sweat pits for tan- 
ners have keptpace with the alterations which have been made 
in the building and location of icehouses for the people 
at large. The same principles govern both. A good sweat 
pit would make a good ice house ; possibly a good ice house 



21 THE LEATHER MANUFACTURE 

might not make a good sweat pit — but only for the reason 
that it would not be sufficiently commodious and controllable. 

In Great Britain it is customary to " steam sweat " sheep- 
skins until the wool yields. This is done by inserting steam 
under a false bottom of a chamber, hung up in which are the 
skins with wool on. The two methods mentioned may be re- 
garded as " warm sweating " in contrast with our system of 
" cold sweating." It may then with truth be claimed that 
our method of sweating is peculiar to this country. 

It is now fully demonstrated that a wood, brick or stono 
structure on the top of the ground can be so completely pro- 
tected from the rays of the sun and other atmospheric influ- 
ences as to make a good sweat pit. The ice companies have 
adopted surface structures of wood, "filled in" with saw 
dust, tan bark or charcoal between the outside clapboards 
and the inside lining of their buildings, and this same form 
of structure will make a most serviceable tanners' sweat pit. 
But since the sweat pit is subject to greater changes of at- 
mosphere than the ice house, it is desirable that the inner 
lining of the sweat pit should be of a more enduring substance 
than wood. The damp but warm atmosphere of a tanner's sweat 
pit decomposes the fiber of the wood very fast— a sound hem- 
lock plank thus exposed becoming worthless in a few years. 
On account of this liability to decay,.if for no other reason, the 
sweat pits of tanners should be constructed of stone or brick. 
But these structures may be wholly above ground, and should 
be so placed that a wheelbarrow may be run from the floor 
of the beam house into the main passage way of the sweat 
I it. These passage ways should be wide— not less than six 
to eight feet-and so thoroughly lighted, both from top and 
ends, as to make the passage through them by the workmen 
both easy and agreeable. The hight of the main passage 
way should extend above the surrounding pits, and by a 



THE LEATHEE MANUFACTURE. 25 

"lantern" construction of the roof both light and air can be 
oecured in the passage ways below. 

The pits themselves should extend from both sides of the 
main passage, and be connected with folding doors, wide 
enough, when fully open, to admit a wheelbarrow. Each of 
these pits should be large enough to contain one pack of 
hides, and high enough to admit the hanging of a side 
doubled, with a space of fully two feet above and one foot 
below the racks, on which or from which the sides are sus- 
pended by tenter hooks. The width of the pits should be 
about eight feet. This will give space for two tiers of sides 
and a small passage to enable the attendant to make his 
examinations. Both this passage and the room above and 
below the hanging sides give opportunity to introduce light 
and ventilation when required. 

There is no reason why these pits should not be so light 
that close observations may be made without the use of a lamp, 
aud they should always be kept in such cleanly and orderly 
condition as will permit the foreman or employer to enter 
and make inspections without fear of soiling their clothes. 
Too much stress cannot be laid on this feature of our more 
modern sweat pits. The fact that such inspections are liable 
to be made at any time keeps a most healthy check on the 
attendant. 

The temperature of the sweat pits should be held under 
control by steam and cold water, with which the main passage 
should be amply supplied by means of pipes. A properly 
constructed pit should have a false bottom, under which the 
steam may be forced, to find its way in condensed spray up 
through the suspended sides. This process will adequatelv 
warm the pit. When too warm, cold water may be thrown 
from the mouth of a sprinkler over the whole surface, ;n id 
thus, in a few moments, cool the whole space, and leave a de- 



26 THE LEATHEB MANUFACTURE. 

sirable moist atmosphere. When in proper condition the 
pits will stand at a temperature of 60° to 70°, F., with globules 
of water collected on all parts of the suspended sides, occa- 
sionally dropping in then condensation from the ends of the 
hair. 

Each one of the pits should have at least four lights, 7 by 
9 inches, in the end, with a lantern ventilator in the top of the 
latter, which can be opened and closed by a cord. The pits 
should be covered on top by timbers flattened on three sides, 
and heavy enough to hold up at least two feet of earth. This 
tli, sodded over and kept well watered, will amply protect 
the pits from the ra} T s of the sun, and the ammonia which 
arises from the pits will produce a most luxurious growth 
of grass, vines or flowers, on this earth covering. The sides 
of the pits should be protected by a banking of earth or 
spent tan. The former is the most desirable, for this earth 
may be made the means of cultivating grape or other vines 
with the most artistic and even serviceable effect. 

With pits thus constructed and under proper control, hides 
may be properly sweat in from three to seven days — usually 
in about four or five days. To accomplish this result the 
hides or sides must be in proper condition. 

For the most part only dry flint hides are prepared by the 
sweating process, in this country, and yet, as we proceed in 
< iur inquiry, possibly we may find that sweating in connec- 
t ion with liming may serve a most useful purpose, particularly 
forgreeu or dry salted foreign hides. The native green salted 
hides are mainly taken by lime tanners, who find no occasion 
to use the sweating process. 

Flint dry hides, or indeed any hides that enter the sweat 
]. it, must first bo made absolutely soft in all their parts— pates 
as well as skirts and butts. In this respect tanners do not 
exercise sufficient care. Where the hides are tender (liable 



THE LEATHER MANUFACTURE. 27 

to break) there is a strong temptation to stop short of this 
desirable condition. Probably less breaking thus results, but 
then " old grain " and " hard spots " will come in to offset 
the breaking. If at any time half prepared, hard sides, 
should go into the sweats, they should go in with companions 
equally delicate and tender in their constitution, and all 
should then be treated alike. 

The sides should be hung on the racks by tenter hooks, 
either suspended from the shoulder or from the pate and 
butt ; whichever way is adopted, the practice should be uni- 
form, so that a uniform result may be anticipated. 

As the sweating process advances with greater rapidity 
in the top than at the bottom of the pit, and as the thicker 
portions of the hide resist the action of the sweat longer than 
the thinner portions, it is desirable, as far as practicable, to 
hang the pates and butts higher than the shoulders and 
bellies, but as this is difficult to manage, the result is accom- 
plished by changing the positions of the sides or hides as they 
advance in the process. Usually, after three or four clays, 
the " assorting out " and changing of position commences, 
and on the fidelity with which this is done will damage be 
prevented and a good result secured. 

No hides, however uniform in character, will sweat exactly 
alike, and it is for this reason that the careful attention of the 
employee must be secured. No hour in the whole day should 
pass without a visit to the advanced sweats. "When a few sides 
give indications of "coming" prematurely, before their proper 
time, they should be dropped to the bottom of the pit, and 
allowed to lie in piles until their less advanced companions 
catch up in the process of decomposition. 

Supposing all the sides to be in the same state of forw ird- 
ness, the present practice is to throw them in the mill, and Eoi 
a few moments wash out or off the slime, and rub the hair off, 



28 THE LEATHER MANUFACTURE. 

or so much of it as can be removed easily. During this short 
and damaging process, two things happen: 1. The loose 
hair is fulled into the flesh so firmly as to make it difficult to 
remove afterward on the beam, and, 2. Much of the gelatine 
of the hide is lost, as at this period it is in very nearly a sol- 
uble c ndition and will part from its proper lodgment in the 
fiber almost as freely as the slime and dirt with which the sur- 
faces are covered ; indeed, much of the substance that is re- 
garded as " slime " and " dirt " is the gelatine, which, when 
combined with tannin, goes to make leather. There is no 
doubt that many of even our best tanners make too much 
dependence on this after milling to soften their stock, and 
with this end in view allow the mills to run on this tender 
stock far too long. 

Some of our most thoughtful tanners have of late, to meet 
this difficulty, thrown the sides when they first come from 
the pits into a weak lime water, and allowed a slight reaction 
to take place. This action of the lime is indicated by a slight 
plumping of the side, and the disappearance of that slimy, 
slippery feel, which always attends sweat stock. Besides 
other savings, this after-liming prevents, to a great extent, 
the hair from attaching itself to the flesh while in the hide 
mill. But beyond these savings I venture to suggest that even 
the slight liming here indulged in will counteract the action 
of the vitriol in the handlers, and to those tanners who use 
vitriol this liming will be of service, for lime and vitriol-will 
counteract and destroy each other. It is well known that 
on purely lime stock vitriol may be used moderately with ad- 
vantage, both as a " bate" and as a means of plumping the 
Leather. 
It has been demonstrated that part liming and part sweat- 
; tlic same hides will answer a very excellent purpose. 
The writer has in his mind an experiment tried on a large 



THE LEATHEE MANUFACTURE. 29 

scale, viz., on 10,000 Texas and New Orleans green salted 
hides, which produced 73 pounds of leather to the 100 
pounds of hide, and the leather thus made was excellent in 
qualit} 7 " — both plump in offals and fine in fiber. If the present 
vitriol-raising process is to be continued, and finis favor, in 
my judgment this partial liming must be resorted to if a 
reasonably good buff is secured. 

"When we are assured, as a justification of our practice, that 
the tanners of Great Britain plump all their bends and butts 
with vitriol, we should remember that this description of 
leather is there made for the most part out of green salted 
hide's from South America or Spain, which are highly limed. 
The English tanners occupy from eight to fourteen days in 
then liming process. The condition of the hide produced by 
this excessive liming will justify the use of vitriol without en- 
dangering the buff or fiber. With our sweat stock it is far 
different "; our sweat sides contain nothing to neutralize this 
mineral acid, and the result is most disastrous to the buff, 
and also to the intrinsic vitality of the fiber. 

There can be no doubt that our American system of cold 
sweating is calculated, beyond any other known method, to 
make a firm, compact fiber, when properly used, and, besides, 
it is especially adapted to the preparation of the dry hides 
of our continent. 

It only remains for me to say a word on the subject of 
" grease " and " salt " as among the hindrances which affect 
and control the sweating of hides. All sweat tanners fully 
understand that the salt (if the hide is salted or pickled) 
must be fully soaked out before the hide will sweat ; from 
this, among other circumstances, is deduced the inference that 
this process is a decomposing one — for so long as the hide 
is h' Id (cured) by the presence of salt, carbolic acid and 
other tawing ingredients, the sweats will not operate on it. 



30 THE LEATHER MANUFACTURE. 

So, too, if the hide is covered with grease — as many of 
our Western and California hides are — it will not sweat 
evenly, owing to the presence of grease on some portions 
more than on others. If the hide is covered all over with 
grease, notwithstanding the action of the soaks and mills, 
then this grease should be removed. This may be done by 
an alkali, such as salsoda, soda ash, potash, etc., of com- 
merce ; when these cannot be obtained, hard wood ashes, 
freely used in the soaks, will turn the grease to soft soap, 
and it will readily wash off in the mills. 

Note. — For illustration and further description oi* improved style of cold sweat 
. as at present in use by American tanners, see engravings in latter part of 
'his book. 



CHAPTER III. 
PREPARATION OP HIDES FOR THE BARK— LIMING. 

GETTING READY THE LIMES — THEIR AGE AND STRENGTH EFFECT OF THE 

LTME ON THE FIBER PLUMPING AND BATING PROF. LTJFKTS's PRO- 
CESS THE "BUFFALO" METHOD THEIR RESULTS HANDLING IN 

THE LIMES. 

By far the oldest method of unhairing the hide is known 
as the " liming process." But old and well established as 
this system is, there are economical and wasteful methods, both 
in the use of lime and in working and handling the hides by 
this process while in the beam house. Without taking up 
the time of the reader by pointing out the defects, let me 
as briefly as possible call attention to the most approved 
methods of using lime for the unhairing of hides. 

Lime for the tanner's use should always be unslaked, or in 
the " stone." When it is supplied fresh from the kiln, as it 
should be at frequent intervals, it should be kept in a dry 
and confined apartment, where neither moisture nor air can 
reach it. This lime should be " slaked " with even more care 
for the tanner than is exercised by the mason and finisher. 

The following description indicates briefly the best method 
of preparing the stone or unslaked lime for the tanner's use : 
Have a half hogshead placed near the lime vat it is proposed 
to replenish ; for a pack of 120 to 140 sides throw in, say, 
one bushel of lime; dampen it by pouring on one or two 



32 THE LEATHER MANUFACTURE. 

pails of water, and cover with a thick canvas ; a few mo- 
ments will suffice to absorb the water, and considerable heat 
will be produced ; add water, gently, several times, rather 
thau " drown " the lirne by an oversupply at any one time, 
and be sure and not allow it to " burn " for want of water. 
The hogshead should be kept covered until the slaking is 
completed. When the reaction is over the tub may be filled 
with water and thoroughly stirred ; after settling, the liquid 
or soluble portion should be poured off into the vat, leaving 
all grit, dirt and unslaked lumps in the hogshead. Nothing 
but pure lime water should ever be allowed to go into the 
vat ; this will not only render frequent " cleaning out " un- 
necessary, but will save the edge of the fleshing knife, and 
shorten the time required in many subsequent operations. 

Some tanners prefer old and weak limes ; others fresh and 
strong ones. Where old limes are depended upon, filled 
with the ammonia of previous decomposing packs, the writer 
would suggest that damage may result unless care is observed, 
for this use of old limes involves in a measure the principle 
of the sweating process. This method, on the whole, may 
be regarded as only suitable to cold weather; in warm 
weather it certainly is too dangerous for general adoption. 

All tanners will, however, recognize the importance of 
making a difference between the process for upper, calf, kip, 
harness and belting leather, and that for sole leather. 

For the former kind of stock not less than three or four 
days should be consumed in the process ; this length of time 
will kill the grease, and fairly plump (distend) the fiber. The 
effect of the alter process of bating is to leave the tissues of 
the hide relaxed and the fiber elongated— just the condition 
in which the fiber should be left in order to make tough, 
tlrxible leather, for when once the fiber of the hide has been 
unduly expanded, and the gelatine cells broken or disturbed, 



THE LEATHER MANUFACTURE. 33 

tliey can never again be brought back to the closed, and com- 
pact condition in which they were found in the natural hide. 
A microscopic examination of the condition of the fiber of 
tanned leather will leave no doubt as to the process which 
has been pursued in the beam house. It is possible so to 
" starve " the leather in the handlers and the after process 
by weak decoctions as to break down the distinct membra- 
nous cells which hold the gelatine, but usually this is done 
in the beam house. If, added to the swelling arid depleting 
process in the beam house, a starving process is followed up 
in the handlers or the layaways, then, instead of plump, well- 
filled leather, we shall notice a stringy, elongated fiber, consist- 
ing for the most part of animal tissues, and, as these do not 
absorb tannin to the same extent that gelatine does, of course 
we have no gain, and have, externally, a coarse, broken offal 
nncl grain. Indeed, we reproduce the examples which we see 
daily coming in from small country yards. The waste which 
this process induces will surely prevent tanners who make 
such leather from reaping large profits or from competing 
with those who make the most possible out of the stock 
which is placed in their hands to treat. 

Three or four days in the lime will not improperly fill the 
hide, and when unhaired it may be speedily reduced to a 
natural condition. This reduction (depletion) will be well 
begun by throwing the hides, or sides, into a wheel, and, with 
a flow of warm water turned on, running for ten minutes. 
The advantage of warm instead of cold water is very marked, 
and warm water may, at this stage of the process, be freely 
used with safety. It is always safe, on hides filled with lime, 
to use heat to the extent of 100° F., or as hot as can be borne 
by thrusting in the hand and wrist. This rinsing process will 
remove the greater portion of the lime, and will ordinarily 

prepare the hides for the liquor; but some tanners are so 
3 



.,4 THE LEATHER MANUFACTURE. 

particular as to insist on bating still more by the use of lien 
manure, or some "sour," such as may be prepared with 
wheat bran or molasses. 

For sole leather this latter precaution is quite unnecessary; 
but for fair or harness leather, and perhaps for calf and kip, 
where not only a clean but a soft grain is demanded, such 
extra bating may be justified. 

Up to this time the treatment of full grown hides only has 
been considered, where they have been handled with lime for 
three or four days. If filled with lime, by being retained in 
the process for six or eight days, more care and more par- 
ticular treatment in the bate may be necessary. But the 
writer would leave all such tanners to work out their salvation 
as best they maj*. This is certainly true, that, as a rule, for 
all upper stock, the hides or skins should go into the handlers 
as free as possible from lime, while sole leather stock may be 
trusted to right itself as it passes through the sour liquors of 
the handlers, provided the fiber has not been unduly strained 
(expanded) in the beam house. 

Thus far the well-known and generally-used methods of 
unlinking by lime have been considered, but there are other 
forms in which lime performs a more or less conspicuous 
part. Referring, in the first instance, to Prof. Lufkin's pro- 
cess, the writer is enabled to state with great particularity its 
details, through the kindness of Mr. Charles Cooper, of Spar- 
rowbush, N. Y., than whom no man has had greater experi- 
ence in its use. Ho has prepared, for several years in suc- 
cession, not less than 50,000 hides by this process, and with 
great success, as the superior leather he has produced will 
it (est. His packs were made up of about 50 hides each, 
either cured, green salted, or dry Buenos Ayres or Bio 
aide. The green hides weighed 50 and the dry 20 pounds 
ich. For such a pack he would slake 80 pounds of stone 



THE LEATHER MANUFACTURE. 35 

lime, in the manner already indicated, except that the lime is 
i.ot watered after the slaking process has been finished 
This leaves the lime of the consistency of a thick paste. 
While in this state take a small portion and knead thorough- 
ly with 10 pounds each of soda ash and pulverized sulphur ; 
when these three products are well mixed, and while the lime 
is yet ivarm, turn the whole in together and mix thoroughly ; 
after doing this take lime liquor from the vat and fill the cask, 
stirring all the while ; when completed pour into the vat and 
thoroughly plunge the whole. No more liquor should be in 
the vats than sufficient to cover the 100 sides when thrown 
in. It is desirable to keep the lime thus made up to summer 
heat by the use of steam, which may be done by inserting a 
steam pipe while the pack is raised. The handling should 
be performed once or twice each day if the hides are thrown 
into the vat in the usual way ; but if handled on sticks or 
reeled, then plunging and more frequent handling will facili- 
tate the operation. 

As to the advantages of this process, the writer would say 
that the sulphur modifies the harshness of the lime and soda 
ash, and renders them almost as controllable in the hide as 
soft soap, for, while the hide may remain in the lime for an 
equal length of time as with the old process, there is not the 
same swelling, nor the same harshness, and a few minutes 
of wheeling in warm water will reduce the pelt to almost the 
consistency obtained in sweat stock. There is no question 
that it is a good method of unhairing for all kinds of hides or 
skins, and when a soft and smooth grain is desirable it is a 
valuable improvement. Of course, it is slightly more expen- 
sive than pure lime, and for this reason has not found general 
favor. 

The next innovation upon the old system of liming may 
be called, for the sake of distinction, the "Buffalo" method. 



3(J THE LEATHER MANUFACTURE. 

This method depends largely upon warm, or even hot water, 
to complete the process. The hide is prepared in the usual 
way, and is then thrown into a strong lime for eight to ten 
hours, when it is taken out and immersed in water heated up 
to 110° R The warm water . soaks, softens and swells the 
roots of the hair, and very much such a result is obtained as 
in " scalding" hogs. So little lime really permeates the inner 
fiber that, after a slight wheeling, the sides may be thrown 
into cold water and allowed to cool and plump, preparatory to 
taking their places in the handlers. The process is strongly 
commended for sole leather, particularly where great firm- 
ness of fiber is desired. The tanner who tries it must be 
satisfied if he gets twenty to thirty sides per man unhaired 
and fully ready for the liquor, per day. 

Besides these, we have many patented methods, both for 
softening and unhairing, but as they are all founded upon 
supposed secrets, and have some powerful alkali as their 
base, the writer will not at present indicate their merits. 
It will be sufficient to say that, up to this time, they have 
made no material progress. 

It now only remains to describe some of the methods of 
handling while in the process of liming. The old method is 
to "throw in" and "haul up" from an ordinary vat — 6 feet 
wide by 8 or 9 feet long. This is so laborious that the sides 
or hides frequently do not get hauled more than once each 
twenty-four hours. Among the labor-saving methods in this 
department the following may be mentioned: 

1. "String" the sides or hides by tying pates and 
shanks together and reel over from one vat to another. [The 
red recommended in Chapter VII., on "Handling," and 
which is illustrated on a subsequent page, will also answer 
for tliis purpose.] 

2. Hang on poles or sticks by throwing the hides or sides 



THE LEATHER MANUFACTURE. 37 

over, resting on the shoulder — butt and pate down. The lime 
liquor is plunged and thus a most perfect agitation and 
handling is effected. 

3. Have the lime vats sixteen feet long ; place the pack, 
while yet in whole hides, in one end, resting on each other ; 
each hind shank should be fastened to a rope or strong string 
five feet long, with a noose at its end, which should be 
dropped over an iron upright at the corner of the vat. If 
this noose is no larger than the iron stanchion, of course the 
top noose will indicate and draw the top hide. One man on 
each side of the vat avlU, by the use and guide of these 
strings, transfer the pack of hides from one end to the other 
of the vat in a few minutes. This system will always leave 
one end of the vat unoccupied, and while thus situated it may 
be "heated up," "plunged" or "strengthened." 

There is an advantage in connection with the latter sys- 
tem which cannot be too strongly urged upon tanners. It 
enables them to lime their hides whole, and to split them af- 
ter the liming process is complete, and this in turn makes 
straight lines. For belt or harness leather tanners this is 
very important. All hides that are split before being limed 
will be crooked and irregular on the " back line," for the rea- 
son that lime takes hold on (contracts) more the thin than 
the thick portions where the whole hide is equally exposed. 
The consequence is that the shoulders contract more than 
the butts. This leads to waste where long straight lines are 
need-"*! in the cutting, as with belting and harness leather. 



CHAPTEE IV. 

PEEPAKATION OF HIDES FOR THE BARK— FLESHING 

AND TRIMMING. 

THE BEAM -WORK CLOSE FLESHING, WITHOUT BREAKING THE GLUE CELLS 

FLESHING LIME SLAUGHTER STOCK WORK TO BE DONE BEFORE 

LIMING FLESHING SWEAT STOCK IT SHOULD BE DONE WITH A 

WORKER THE GERMAN FLESHER TRIMMING CROP LEATHER AND 

BACKS ADVANTAGES OF TRIMMING UPPER AS WELL AS SOLE 

" ROUNDING " TRIMMING BEFORE TANNING BEST METHOD OF 

UTLLLZLNG THE HEAD, PATE, ETC. 

By far too little attention is paid to beam work by Ameri- 
can tanners. No amount of labor or care in the after process 
can atone for neglect in this department. The flesh should 
all be removed, and the natural structure of the hide should 
not be disturbed or even touched with the edge of the flesher. 
The difficulty of accomplishing this with the careless, unap- 
preciated and unrequited labor at present employed in this 
S( nice, is great ; but when tanners come to understand that 
both national and international tastes and wants demand 
that this work be properly performed, there will be no diffi- 
culty in securing the necessary reform. It is estimated that 
the additional fleshing will cost, in labor, three cents per side 
with lime stock and two cents per side for sweat stock, while 
it will deprive the side of about one-half a pound of fleshy, 
fibrous matter, when tanned. This, then, is the sacrifice 
tanners are required to make in order to meet the foreign 



THE LEATHER MANUFACTURE. 31) 

demand and taste, as well as give better satisfaction to con- 
sumers at home. 

If the question was between removing the flesh and cut- 
ting the cells that contain the gelatine on the one hand, or 
leaving all the flesh on and retaining the structure of the 
hide intact, tanners should of course prefer the latter ; but 
there is no such alternative. The flesh may be removed with- 
out injury to the structure of the hide, and this should be 
done by all tanners who pretend to commendable workman- 
ship. A clean flesh is desired not more by our own manufac- 
turers than it is demanded by those of Europe, and both 
should be gratified. If persistent and dogmatic statement 
will accomplish reform in this important department of the 
tanner's art, the writer proposes to use both in the way of 
entreaty and admonition. 

The fleshing of "lime slaughter stock" and of "dry hide 
sweat stock" are quite different operations, and must be con- 
sidered separately. 

Our practice in regard to the first class is to throw the 
hides into the soaks for a day or two — just long enough to 
cleanse all the blood, salt and other impurities from them — 
then draw from the soaks and split, and throw into the lime, 
paying no attention to the flesh until they come on the beam, 
after passing through the lime. The hide is plumped by the 
action of the lime, and the theory is that, when the flesh is 
thus swollen and raised, it may be removed with less danger 
than if done before the hide was plumped. This is undoubt- 
edly true, if only the same labor and skill is to be employed 
in each case. But, on the theory of accomplishing fully what 
we concede to be desirable, the " meat " must be removed 
from the flesh before the hides go into the lime, and the meat 
should be "worked off," and not "cut off." The "cutting 
off " implies skilled labor, but the "working off" is more 



40 THE LEATHER MANUFACTURE. 

economically done by willing, unskilled labor. When the 
meat on the hide (which should have been left on the carcass) 
has been removed, two things will be accomplished : 1st. The 
action of the worker will have, to some extent, broken (dis- 
tended) the nerve of the hide ; and, 2d. All obstruction to the 
uniform liming of the hide will be removed, for patches of 
moat on the flesh side obstruct the action of the lime, as all 
good tanners concede. 

When it becomes fully understood among tanners that 
all the flesh from slaughter limed stock must be removed 
not only in the beam house, but while the hides are whole 
and before they go into the lime, it is not unreasonable to 
suppose that some mechanical contrivance will be devised to 
accomplish the work. At present we are compelled to over- 
come this obstacle by manual labor, and hard, disagreeable 
work it is. But the actual money cost is not more than six 
cents per hide, and as this labor, thoroughly performed, will 
render the after beam work much easier, the writer ventures 
to say that no tanner making this stock can long resist the 
innovation. Many of our upper and harness leather tanners 
<lo at present remove the meat before liming, but the practice 
is not general. In another chapter the reason for liming the 
hide whole has been explained, and that subject need not 
here be entered into. 

The fleshing of sweat stock is quit ) different from that 
necessary where lime is used. The beam hand is always cut- 
ting or working on a soft, pulpy substance, and should never 
use the edge of the flesher except to trim the edges or cut 
the filmy portions attaching to the flesh. All extraneous flesh 
and hair may be readily Avorked off from sweat stock for the 
price already indicated, by a fine tooth worker; but these 
t< eth, if long and sharp, are likely to cut the outer cells of 
the liber. It would be better to remove the flesh with a 



THE LEATHER MANUFACTURE. 41 

p nooth-edged worker, which may be done at a cost not to 
exceed two cents per side. The saving in the amount of flesh 
and tissue removed, and the damage avoided from the catting 
of the fiber, will amply repay the extra cost. There are two 
machines, either now offering on the market or soon to be 
introduced, one of which proposes to remove the flesh while 
in the beam house — the power beam worker, of Mr. Lampert, of 
Rochester, N. Y.— and the other is intended to shave or cut 
the flesh off after it is tanned — the new buffing and whitening 
machine, introduced by Mr. Caller, of Salem, Mass. But 
until one or both of these machines have demonstrated the 
success which is claimed for them tanners had better work 
off the flesh, as already indicated. 

The usual flesher and half round beam are too familiar to 
the tanner to require notice in this connection, but within a 
few years the French and German beam knife has been in- 
troduced into this country and received with general favor. 
This knife is about one-third longer than ours, and is not 
more than two inches wide ; the material is the best steel, 
and the knife is not more than a quarter of an inch in thick- 
ness on the rib or center. The blade is so supple that the 
handles can almost be brought together. It is claimed for 
this knife that, by bending round the convex form of the 
beam, it makes a flatter cut on the flesh of the side, less con- 
cave than a stiff, straight-edged flesher cutting on an oval or 
convex surface. To this extent the new knife certainly does 
present advantages, and may be safely trusted to do good 
work in skillful hands. 

In the year 1838, a tanner in the State of New York,, in 
obedience to the suggestion and order of a manufacturer of 
boots and shoes, commenced to "crop" his sole leather. 
The full extent of the demand at first was 100 sides per week. 
This demand grew, as other manufacturers came to see the 



42 THE LEATHER MANUFACTURE. 

economy of the practice, until 2,000 sides per week were re- 
quired in 1844. And now, in 1876, probably not less than 
1,000,000 sides of " union crop and backs " are manufactured 
yearly in the United States, and sold both in this country 
and Europe. Within a year or two the " crop " form of 
trimming has largely given way to the "back" form. The 
latter differs from the former only in the removal of the pate, 
at the point where the throat is usually cut, which makes the 
shape of the side more compact, and in harmony with the 
"bend" leather of Great Britain. There must be some ad- 
vantages in this method of trimming, or otherwise the trade 
would not have grown so rapidly, and, to acknowledge this, 
is to concede that still other improvements may be made. 
Let us inquire what they are. 

The tanners of Great Britain, who certainly studv the 
economies of their trade more thoroughly .than the same 
class in any other country, not only trim the bellies, but also 
the shoulders, from their butts and bends. The following 
reasons may be assigned for their practice : 

1st. The shoulders and offal are much thinner than the 
butts, and therefore tan in shorter time. 

2d. The offal being used where a tough fiber is required, 
slack, or, at most, a full tannage is all that is required. 

3d. The boot and shoe manufacturers, not only of Europe 
but of America, have so classified their work that those 
who use butt leather largely do not require so much " inner 
soling" and "welting" as would come from the bellies and 
shoulders of the hides which would give them just the de- 
scription of sole leather required. 

But the upper leather tauners of Great Britain also trim 
(round) their upper leather, notably so their East India kips. 
The good Bense displayed in this process should be adopted 
1 >y the tanners in this country, particularly on all East India, 



THE LEATHER MANUFACTURE. 43 

"Russian or native murrain kips. The bellies and shouldeis 
of these, when finished on the grain, make a most ser- 
viceable leather for women's and children's shoes, while the 
butts, finished on the flesh, answer for a stout boot or shoe. 
This method of rounding light upper sides and kips recalls 
the economy of our fathers, when it was customary to make 
"magpie" leather — that is, grain and wax finished on the 
same piece. The farmer had his single hide, taken off in the 
fall, tanned by the halves, and finished "magpie." This gave 
him the thin bellies and offal, grain blacked for women's and 
children's shoes, and the thicker portions, "waxed," for wear 
by himself and older sons. One of these days we shall imi- 
tate the economy of our fathers, and treat the whole shoe 
and leather consuming people as one family, whom it is our 
duty to supply with leather fabrics upon the most economic 
plan, and when this time arrives we shall find ourselves imi- 
tating very closely the habits and practices of the leather 
and shoe manufacturers of Great Britain, for they are, no 
doubt, far in advance of us in all these respects. It is prob- 
ably true that the population of Great Britain is better and 
more economically shod than any people in the world. A 
portion of the economy is due, however, to iron rather than 
leather. Much of the economy here conceded arises from 
their method of trimming and Tounding their hides and skms. 
That which belongs to the glue maker never goes beyond the 
beam house in any tannery in Europe, and tliis includes the 
hide from the pates, heads, shanks and tails. In treating of 
the " savings of the tan yard " their methods of utilizing 
these as well as the hair and other serviceable offal will be 
explained. 

Our best city custom harness makers can scarcely real- 
ize the fact that, until within a few years, they have been 
compelled to buy the offal of all the sides they cut. Now 



41 THE LEATHER MANUFACTURE. 

they buy only the backs, or just such portions as they need, 
while the trunk, collar and strap leather manufacturers can 
get their supply from the bellies of these sides. This eco- 
nomical arrangement we borrow from Great Britain. 

There is one advance, however, in the economies of leather 
trimming and cutting which owes its origin to Lynn, Mass., 
viz., the cutting of soles, and sorting them to suit each spe- 
cial manufacture. This gives each w r hat he requires, and 
only that. Upper and calf fronts are furnished in a similar 
way to manufacturers in all Southern Europe, but, so far as 
the writer has observed, the practice of furnishing soles to 
large manufacturers is confined to this country. 

The trimming of hides used for belts, bags, and more re- 
cently for enameled leather for carriages and furniture cov- 
ering, should by this time be familiar to all. The practice, 
however, marks an advance in the progress of the art which 
gives promise of infinite extension and profit. ' 

In closing this chapter the writer wishes to offer a sugges- 
tion. The head of the ox or the cow is now skinned while 
yet attached to the body, and, as it is done by the usual 
skinner, who comprehends that the hide is more valuable by 
the pound than the coarse meat, he leaves as much of the 
meat as possible on the skin rather than the head, and this 
policy will probably continue until the head is severed from 
the body while the skin remains on, and is in this condition 
handed over to men or women whose special training will 
induce them to skin the cheeks and throat together in one 
piece, leaving the "pate" proper to be skinned and wholly 
handed over to the glue maker. If this is carefully done, 
the skin of the cheeks and throat will give four or five feet 
of fine grain leather, besides two or three pounds of glue 
ck, for this head piece should be split while in the lime, 
and only the grain sent into the yard to tan, while the split 



THE LEATHER MANUFACTURE. 45 

portion should go for glue. The nose and lips should be cut 
off while fresh, and handed over to the sausage makers, who so 
well understand how to scald, piclde and prepare these deli- 
cate morsels for human food. The meat should be carefully 
cut from the head while fresh, and made into sausages. The 
bone, including the pith of the horn, should be crushed or 
ground into a fertilizer, and the horns handed over to the 
button or comb maker. 

Many of these processes are now adopted in the final dis- 
position, but all are retarded, and the result injured, by the 
mistake of skinning the hide from the head while attached to 
the carcass. Let the tanners consent or insist on this sepa- 
ration of the head when they buy their hides, and we may 
depend upon immediately taking one step forward in the di- 
rection of a more economical method. 



CHAPTEE V. 
GRINDING BAEK— BARK MILLS. 

THE INEXPENSIVE AND .ABUNDANT POWER OP SOLE LEATHER TANNERIES 

GRINDING BARK FINE AND UNIFORM USEFULNESS OF SCREENING THE 

GROUND BARK THE DOUBLE-GBINDLNG MILL ITS EFFECTIVENESS 

WITH DAMP BARK THE ALLENTOWN MILL ADVANTAGE OF A STRONG 

MILL AND WEAK COUPLER THE SAW CUTTING MILL A BABK CRUSH- 

ING MACHINE — THE PBOPEB SPEED AT WHICH MILLS SHOULD BE RUN 
TANNIN LEFT IN THE BARK. 

It will be conceded by all practical tanners that the prep- 
aration and proper grinding and leaching of bark stands at 
the head of all the economies of the tanner's art. The very 
Large number of imaginary and real improvements made in 
this department are so many concessions to the importance 
which is attached to it by tanners and inventors. Patents 
almost without number have been obtained on bark mills and 
their attachments, and on leaehes and their various methods 
of heating and handling. Life is too short and space too 
limited to review all these improvements and patent claims. 
It will be sufficient for the present purpose to indicate the 
methods and processes which have gained the most general 
adoption in our largest and best constructed tanneries. 

The successful burning of wet spent tan in detached fur- 
naces has, more than any one or all causes combined, con- 



THE LEATHER MANUFACTURE. 47 

tributed to a reform in the grinding and leaching of bark. 
Whether to furnish the motive power to grind the bark, or 
the heat to extract the strength, wet spent tan has afforded 
a substitute for water power and wood or coal fuel, and has 
proved so complete a substitute that all previous expedients 
have been abandoned. So absolutely inexpensive is this 
material that power and heat may be used without stint or 
limit in the manipulations of all our modern sole leather 
tanneries. " Sole " leather tanneries are particularized be- 
cause upper leather tanners usually are in short supply of 
refuse tan to do all this work, and they even now find it prof- 
itable to dry or partially dry their tan, with all the improve- 
ments for burning wet spent tan open to their use, thus prov- 
ing that " water " does not increase the heat-giving proper- 
ties of tan, but diminishes them, notwithstanding the learned 
opinions of experts to the contrary. 

The fact then stands conceded that the wet spent tan from 
an ordinary sole leather tannery will give ample power to 
grind all the bark and heat all the liquor required. If any 
further saving of labor can be suggested by the use of more 
power and more heat, they can readily be obtained by the 
surplus tan now thrown away. Therefore we go into the 
economic consideration of this question with an absolute me- 
chanical power without limit. The tanner may grind to any 
degree of fineness ; he may screen and return to the mill any 
portion of his bark ; he may convey up or down, or laterally, 
to any required distance, either his dry or spent tan. With 
such power, if he fail to extract the whole strength, and do 
it in the most acceptable and satisfactory manner, he has no 
one to blame but himself. 

The importance of grinding bark fine, and yet uniformly 
so, without dust on the one hand or large coarse lumps on 
the other, is conceded to be very great. Dust obstructs, and 



48 THE LEATHEE MANUFACTURE. 

coarse lumps prolong the process of leaching. Imperfect 
grinding does more : it necessitates the use of extreme heat 
to extract, whereas if the bark is uniformly and properly 
ground very little artificial heat will suffice in winter, and no 
more heat than that of water at the ordinary temperature 
will be required to extract the tannin in summer. 

For more than forty years tanners have been seeking the 
best bark mill. In this respect they are like the farmers 
who seek the best plow. Both bark mills and plows are com- 
parative, not positive, in their character and attainments. 
Before determining in any given case just what mill should 
be adopted the circumstances should be known. If the 
tanner has purely hemlock bark or purely oak bnrk, and, 
moreover, if these barks vary in condition, being sometimes 
damp or wet and at other times dry, these conditions should 
be known before an intelligent opinion can be given as to his 
wants. 

For the grinding of all kinds of barks, with the most varia- 
ble conditions, I judge that the "double grinder," formerly 
known as the " Starbuck " or " Troy" mill is preferable. The 
patent on this kind of mill has long since run out, and it is 
now manufactured at various tanning centers, but while all 
are essentially the same in construction, their "fitting up" 
makes the difference between a serviceable or worthless mill. 
A double grinding mill, carefully fitted, will grind damp or 
wet bark with more success than any other mill, and for the 
reason that its grinding surfaces are open — set with obtuse 
angles — rather than close, with sharp, acute angles. There 
is no reason why this mill may not always hold a respectable 
position among tanners when proper care is bestowed upon 
the castings and fittings. 

The most artistic, and, on the whole, the most economical 
mill yet presented for our adoption is the mill made by 



THE LEATHER MANUFACTURE. 49 

Messrs. Win. F. Mosser & Co., of Allentown, Pa. This mill, 
at first, costs about $70 to $80, but may be renewed for 
from $6 to $10 for an indefinite period. The principle on 
which it is constructed must be approved by all, and cannot 
fail to be generally adopted. Its large cost lies mainly in the 
original "fitting up." The shaft or spindle is made of wrought 
iron (or should be so made), and is carefully turned at its 
bearings. The bowl and curb are also turned true, and seg- 
ments, either of cast iron or steel, are bolted on these turned 
surfaces. This form of construction gives a true and adjust- 
able grinding surface which leaves nothing to desire. These 
segment surfaces can be either sharpened with a cold chisel, 
or a "saw gummer" run by power, or may be renewed with 
new iron or steel segments, for the inconsiderable sum above 
named. The original cost of a mill then is of small conse- 
quence. It is the cost of frequent renewals that makes the 
expense of grinding with such mills so great. By far the 
largest replacement is made necessary by breakage, and not 
by wear, and hence the importance in saving the original and 
more costly structure. This is done in the case of this mill 
by a safety coupling, which renders breaking by the usual 
casualties impossible. 

So confident was the possessor of one cf these mills that 
no accident would result by throwing in iron, that, in my 
presence, and against my earnest protest, he threw in an iron 
bolt with the bark. In a moment a slight " click " was heard. 
The mill stopped, but the driving shaft went on. The coup- 
ling only had broken (this being the weakest point). This 
coupling costs only seventy-five cents. In ten minutes the 
step of the mill was lifted into a new coupling, the iron 
picked out, and the mill started as usual. 

If this safety coupling can always be relied upon, then, 
beyond the original cost, a new mill can at all times be. 



~)Q THE LEATHER MANUFACTURE. 

procured of iron for $6, or of steel for $10, and this replace- 
ment is made necessary only after repeated sharpening of 
the grinding surfaces by the ready means already indica- 
ted. Two hours will suffice for removing, grinding and re- 
placing one set of these segment surfaces, and so true do the 
mills run that they will " crack corn " successfully, or would 
he acceptable coffee grinders for a large army of men. 

There is one thing, however, that these mills will not do. 
They cannot successfully grind damp or wet bark, and it may 
be doubted whether, in the nature of iron-mill construction, 
a close and fine bark grinder can be made to perform this 
difficult service. This is a problem at which the owners of 
the mill are now at work. Whether they succeed or not, it 
is certain they now have the best, and, all things considered, 
the cheapest bark mill known in this country, and for the 
grinding of dry bark it leaves nothing to desire. 

It has always been difficult in practice to secure absolute 
uniformity in grinding, even by the newest and best iron 
mills. The defects of grinding can be overcome by the erec- 
tion of a screen or wire sieve, stretched over a revolvino: 
skeleton frame of wood. The meshes should be three-six- 
teenths of an inch square, and, thus constructed, may be re- 
lied on to " bolt out " all the coarse particles, and send them 
back to the mill to be reground. This inexpensive contriv- 
ance will cover the defect of leaving too coarse particles in 
tin' ground bark, whether these come from an imperfect mill 
mi' an old, worn-out one, and no tanner can safely do without 
it, With the " Allentown miU " the screen will have less to 
do, but even with this uniform grinder a screen is useful. 
With a properly constructed screen, almost any mill, what- 
ever its condition, maybe trusted, as its defects can never 
reach the leach. 

The limited service now performed by this screen only par- 



THE LEATHER MANUFACTURE. 51 

pally indicates its possible usefulness. There is no reason 
why all the bark from the mill may not go into a tight inclos- 
ure supplied with wire " bolts " or screens that will make as 
many classifications of the ground bark as, in the judgment 
of the tanner, are demanded. The dust should be sent to ? 
leach made specially to extract its strength. This may be a 
revolving square or round leach, with inside projections to 
agitate the contents, or may be a leach with a round bottom, 
with a paddle wheel revolving on and in its top surface, for 
the purpose of keeping for a time the dust floating in the 
weak liquor or water. This bark dust so readily yields up 
its tannin that almost any contact with warm water will suf- 
fice to denude it of its tanning properties. "When the dust is 
all separated from the remainder of the bark, the leaching 
will proceed rapidly, as the circulation is less obstructed. 

Of course tli3 ground bark of this screening process can be 
graded to suit either the leach or the layaways. The latter 
service requires a much coarser bark than the former, and, by 
careful screening, bark of any particular size which may be 
needed can be obtained. 

The question is often mooted as to the degree of fineness 
to which bark may be reduced for advantageous leaching. 
The answer is, as fine as the "percolation" or "press sys- 
tem " of leaching will permit. If all bark could be reduced 
to a uniform size, "buckwheat" or "cracked corn" would 
nearly represent the condition most favorable for the ready 
and economic extraction of the tannin from the bark. 

Within a few months another example of " saw grinding " 
or cutting of bark for tanners' use has come to my attention. 
The work performed by this machine is admirable, and if 
clone with the ease and rapidity stated by those interested, 
then it promises to divide with the best bark grinder the 
patronage of our tanners. The promoters of this sawing ma- 



52 THE LEATHER MANUFACTURE. 

chine, however, seem to think that their machine is new. In 
construction it may be, but not in principle. 

The numerous other mills made are not here mentioned, 
not because they have no merit, but mainly because their 
advantages are so varied and disproportionate to their num- 
ber that it would take up too much space and time for their 
presentation. Most of the bark mills which have considera- 
ble merit, and have been largely introduced to the trade, 
have had their specially commendable points presented to 
our tanners through the columns of the Shoe and Leather Re- 
porter during several years past. But the writer has these 
suggestions to make to bark mill manufacturers : Take great 
pains in fitting up your mills ; make your grinding surfaces 
replaceable, and have them run true, so that what bark goes 
through is not ground to a powder, but in uniform particles ; 
adopt a safety coupling, so that a valuable and even a high 
cost mill can be indulged in by all tanners at an inconsidera- 
ble aggregate outlny. 

On this subject it now only remains to call attention to a 
"bark crushing" and "extracting" machine, which came to 
the attention of tanners a few years ago, but has now been 
forgotten by its failure, and is here mentioned to call atten- 
tion to the fact that bark crushing, like bark sawing, has been 
tried. This machine was a most ponderous affair. It con- 
sisted of a series of metal rollers, through which the un- 

mnd bark (bark in the leaf) was passed after having been 
si -.iked in hot water for an hour or more. It was claimed for 
this process of squeezing that nothing but the fine "salts" 
would come out, leaving all the resin and much of the color- 
ing matter behind. The report which was made on the prac- 
tical working of this costly experiment was to the effect that 
th.' bark (hemlock) was thoroughly crushed, and a portion of 
the tannin was squeezed out, but that much remained. It 



THE LEATHEE MANUFACTURE. 53 

was conceded that the bark was most admirably prepared for 
leaching, being left in the form of a "pulp." But the ma- 
chine was expensive, costing fully $1,000, besides requiring 
30-horse power to drive it, and, while interesting as an ex- 
periment, was a failure for practical work. When last heard 
from this machine belongsd to a corporation or association, 
and was started in Tennessee to make oak extract. 

It is quite common for patentees and even tanners to over- 
estimate the amount of bark ground per day or hour by their 
mills. It is a good mill that will average one cord per hour, 
although we hear reports of the grinding of one and a half 
and even two cords per hour. But bark ground at the rate 
of one cord per hour and well done is far more profitable 
than more rapid work. The writer has seen a mill grind one 
cord in fourteen minutes. The mill was, however, "geared 
up" to 280 revolutions per minute, and ground the bark very 
coarse at that. 

This leads me to say that a slow motion is desirable. It is 
questionable whether a motion of over eighty revolutions per 
minute is either profitable or effective ; certainly the benefits 
can in no wise overbalance the defects in grinding and dan- 
gar of fire arising from excessive friction. A quick motion 
has the effect to "throw up" and "back" the bark, rather 
than to take it in and pass it through the grinding surfaces, 
as a slower motion will. The best experience has demon- 
strated that eighty revolutions on a small and seventy revo- 
lutions on a large-size mill is the proper motion. Airy faster 
motion, besides the loss of power involved, will not propor- 
tionately increase the result, and will, besides, greatly in- 
crease the fire risk. 

The time may come when hemlock and oak bark will be- 
come so scarce and dear as to necessitate other means than 
grinding and leaching for getting the strength out. It is now 



54 THE LEATHER MANUFACTURE. 

estimated that from 7 to 10 per cent, of the strength is left in, 
arid it has been doubted whether any of our present methods 
will take out that small remainder profitably. The English 
tanner, who pays from £5 to £7 per ton for his bark, would 
pitch the leach over once or twice, releaching each time until 
the last particle of strength was out. The German tanner 
would use his bark on his layaways for two or three months, 
and then take the last strength out by leaching. All these pro - 
cesses are so different from ours that we cannot avail our- 
selves of their tedious methods. The time may come when 
it will pay to pass the partially spent tan through metal roll- 
ers, thus breaking and crushing the unspent portions. So 
far as the power is concerned, this could be afforded now ; 
1 >ut the labor of passing the tan out of the leach and through 
these rollers, and then again back into the leach, would cost 
more than the small percentage of strength gained would be 
worth. 

Some illustrations of bark mills, and sectional parts of 
mills, with further description of their working, will be 
found in subsequent pages. 



CHAPTER VI. 
LEACHING. 

TANNIN VS. KESINOUS AND COLORING MATTER TANNIN REQUIRED TO MAKE 

GOOD WEIGHT EXTREME HEAT IN LEACHING INJURIOUS FLOODING 

THE BARK THE PRESS LEACH HEAT TO BE APPLIED ONLY TO THE 

WEAKEST LEACH CONSTRUCTION OE LEACHES CLAY AND LOAM PACK- 
ING FOR THE SIDES AND BOTTOMS WORKING THE PRESS LEACH THE 

SPRINKLER LEACH REVOLVING DETACHED LEACH. 

The full and perfect extraction of all the tannin from the 
bark is not only desirable, but is of primary importance ; it 
is equally essential, however, that this subtle elixir should be 
extracted without deterioration or injury. It is found in 
practice not at all difficult to wash out all the extractive or 
soluble matter from bark, but to separate and take out the 
greatest amount of tannin, leaving the largest portion of col- 
oring and resinous matter behind, is quite a different thing, 
and one which has taxed the efforts of our best tanners. The 
system of leaching which will best enable the tanner to con- 
trol and separate these qualities is, in my judgment, the 
one to be most commended. In fairness it ought to be said, 
however, that there is much difference of opinion on this sub- 
ject among some of our largest, and, financially, the most suc- 
cessful of our tanners. 

Their theory aud practice must proceed on the assumption 
that coloring matter will give weight, when incorporated with 
the hide, and that the resinous matter will in some mysteri- 



5g THE tSATHEB MAJTOFACTUBE. 

ous way attach itself to the leather, defying the action of the 
ab ber to wa.h it out. This, to the writer, is a dangerous 
heresy and should be rejected unless there are tacts and 
considerations favoring it which have never been presented 
to the public, for to it may be justly charged all the defects 
in color which for so muiy years baffled our hopes of a suc- 
cessful foreign market. It has also caused other defects, 
both of finish and quality, which it will be more appropriate 
to consider in another place. 

The commencement and successful continuance of the 
"union" sole leather trade, both in ''crop" and "sides,"' has 
demonstrated that it is possible to make a light, fair color 
while using hemlock bark. With such experience as the man- 
ufacture of this description of leather famishes, the writer is 
prepared to defend the position here assumed, viz., that tan- 
nin, and not coloring or resinous matter, enters the fiber and 
uives weight. All the illustrations or seeming proofs to the 
c< .ntrary are drawn from heavy sole leather tannages. There 
is an inherent inequality in the conditions of the two kinds 
i »f tannaga which will fully account for the disparity in weight 
made under each, quite independent of the conditions we 
are combatting. It would be unfair for me to assume 
the correctness of my theory from the fact that a given 
quantity of bark will make more light colored leather than 
-lark, for bark will go further, as all know, in light wekht 
tannages than in heavy. This is illustrated by the well- 
known fact that one ton of hemlock bark will tan 300 pounds 
of upper leather, while it will only tan 200 pounds of sole 
leather. It would be as unfair for me to assume that this 
difference was creditable to the absence of the extra coloring 
and resinous matter, as if would be for those who differ from 
me to assume the opposite conclusion. 

The success and value of any system of leaching must de- 



THE LEATHER MANUFACTURE. 57 

pend upon the intrinsic or serviceable value of the liquor or 
extract obtained. If liquor obtained from the bark without 
heat will make leather that will bring in the market one cent 
per pound more than leather made with an extract obtained 
by extreme heat, then it is clear that a cold or more moder- 
ate process is preferable to the hot water or steam process, 
provided all the other conditions are equal. 

The "union crop" leather tanners have learned to compre- 
hend the value of moderate instead of extreme heat, and when 
better methods of grinding and screening the bark shall be 
appreciated at their full value, even less heat than at present 
will be employed by them ; the more nearly summer heat 
(60°) is adhered to on the head leach, the more modified and 
controllable will be the color. This view of leaching was 
maintained by Mr. James Clewer* during all his American 
experience, and it must be conceded that he produced as 
satisfactory results as any tanner, either before or since his 
time. He frequently demonstrated his ability to make 190 
to 200 pounds of leather with one ton or cord of bark, and 
he never used more than summer heat on his head leach ex- 
cept in winter. 

There have been during the past forty or fifty years a great 
variety and many forms of leaches and leaching processes. 
Previous to this period, viz., about 1820, leaches were not 
used to any considerable extent for new bark. A single vat 
was set apart into which aU the old layaway bark was cast 
for final washing, but this was the extent of the leaching 
process ; and if the writer's observation and information can 
be relied upon this sytem prevails now in most of the coun- 



*An English tanner who came to this country about the year 1829. He was a 
practical workman, and had -" 

tanning as almost any one in fl I at that - ntry 

or Great Britain. His work and experiments among onr tanners were of lasting 
value in materially advancing the trade in many particulars. 



oS THE LEATHER MANUFACTURE. 

tries in Southern Europe. No country now so universally 
employs leaches as our own ; and, therefore, we can draw no 
lessons from their larger experience, as in many of the other 
departments of our leather manufacture. 

There are in this country three distinct systems or meth- 
ods employed for leaching bark, but a much greater variety 
of forms. For the sake of designation we may call the first 
a " douse," the second a " press," and the third a " sprinkler " 
leach. The douse leach is the oldest known method. It is 
the one used from 1824 to 1832 by the hemlock tanners who 
made their way into Greene, Delaware and Schoharie coun- 
ties, in the State of New York, at that early period of our 
tanning history. Usually one leach was placed on the top 
of another. The top leach had a heater of some form con- 
tained within it, by which the liquor and bark were " heated 
up," even to the boiling point, and the liquor was finally 
dropped down on a leach below, usually also containing bark, 
but not always, for, when stationary, it was found difficult to 
so run them as to wash properly the weaker bark ; usually 
the upper and lower leaches, however, were filled at the same 
time, and worked together as one leach. Any leach, or sys- 
tem of leaching, may be said to belong to this class that 
floods the bark and allows the whole bulk to remain saturated 
and stationary. Even where the leaches are pumped over 
from one to the other, if the contents are allowed to stand, 
and the liquor is then drawn off in bulk, the leach belongs to 
this class. 

The " press" leach was introduced into this country by Mr. 
James Clewer, about 1830, and the method was improved, by 
his own suggestions, from some leaches which he had worked 
in England. His system washes out the extractive matter, 
including the tannin, "by column," as contradistinguished 
Erom the "sprinkling" or percolating method introduced by 



THE LEATHEB MANUFACTUKE. 59 

Allen & "Warren, which is the third distinct process, as is 
claimed ; and yet it will be seen by close observation that 
these last two methods resemble each other very much in 
principle, since both move constantly from the weaker to the 
stronger bark. The one passes by column and the other by 
percolation, and that is the only difference. 

Keeping in view the three general divisions or classifica- 
tions of leaches, let us go back and consider them in their 
order. The douse leach may be of any size or construction. 
It may be round or square. It may be filled with bark and 
the liquor or water run on, or the bark may be run on with 
the liquor (floated from the mill). This leach may be heated 
up in any way, either by inserting steam under the false bot- 
tom, or the liquor or water may be heated before it is run on. 
This process of flooding and "running up" and " off," either 
with or without heating, is even now much practiced, and, 
but for the fact that it tends to dilute the liquors in the yard, 
is very satisfactory. But this dilution, or want of concentra- 
tion, is an evil which all tanners deplore and desire to avoid 
in heavy tannages. For upper, harness, and calf, it will do 
better service ; but, for reasons presently to be stated, there 
is less thoroughness in the leaching than by either of the 
other methods, for it must be evident that the discarded bark 
must have retained the strength of the last liquor that has 
passed off, and for this reason can never be perfectly denuded 
of its tannin. 

The usual or best form of constructing and working the 
press leach may be stated as follows : The number of leaches 
in a set should correspond to the number of days in the week, 
or the number of full leaches required, multiplied by the 
number of days in the week, thus, 6, 12, 18 or 24. According 
to my judgment, six leaches in a set are always better than 
any other number. By this plan one new leach is filled in 



CO THE LEATHER MANUFACTURE. 

each set each day of the week, and if more than the capacity 
of one leach is required for the day's work, then the sets of 
leaches should be multiplied, rather than to break into the 
system as here contemplated. This will give at least five 
days for the leaching of all the bark, and this time is ample 
and more than enough. Too many tanners, however, when 
crowded, break into their plan, and attempt to force two 
leaches a day from a single set, which creates confusion and 
leads to waste. 

Under no circumstances is heat applied to any other than 
the back or weakest leach. This will bring the strong liquor 
of the set on the head leach comparatively cold, or at most 
at summer heat. Such a course will bring all the liquors 
passing through the yard into a proper condition to go upon 
the leather without coolers or waiting. It will also do much 
more ; it will leave behind much of the coloring and resinous 
matter, and send forward a pure tan liquor, free from all sedi- 
ment and impurities. 

The form may be square or round, depending on the situ- 
ation of the ground where placed. Where it is possible, this 
kind of leach should be set in the ground on a level, and well 
filled in with clay or loam. Exceptionally the writer has seen 
them set on a side hill — one raised six or eight inches above the 
other — but it is safe to say that, when placed in sets of not 
more than six, there will be no difficulty in working the press. 
When placed in the ground and filled in with loam, they 
should be, in size, 6 by 6, 8 by 8, 10 by 10, 12 by 12 feet, etc., 
their capacity being regulated by the size of the vats in the 
yard. 

It may be well here to mention a fact that is not generally 
known, viz., that loam is quite as good as clay for pack- 
ing for the sides and bottoms of the leach, if only properly 
prepared. The preparation consists in mixing the earth with 



THE LEATHEE MANUFACTURE. 61 

w°ter to tlie consistency of tliin mortar in a vessel before it 
is poured in between the vats or leaches. If so mixed and 
run in, a solid sandstone formation will result. To be con- 
vinced of the efficiency of this method of filling in between 
leaches, try this experiment : Take an ordinary pail and fill 
it with loam ; while doing so pour in water, so that when 
filled there will be a thick earthy substance ; stir up well and 
let it stand for one day. The water will all be on the top, 
and the earthy portion will have gone to the bottom, each 
particle in its order of specific gravity. These particles will 
so compactly adjust themselves as to form a solid stone. In- 
deed, geology informs us that this is the way that sandstone 
is formed in the earth. You may bore any number of holes 
in the bottom of the pail, but no water can pass. The water 
will in time evaporate from the top, but cannot escape other- 
wise. Unless great care is observed this concrete will force 
the sides of the vats or leaches in ; or, still worse, raise them 
from their beds, by working under and pressing them up. 
To avoid this, water should be run in to fill the vats as fast 
as the concrete fills the outer sides or passages around and 
between. It is never safe to trust to studding to keep the 
new and empty vats in place. Mr. James Clewer used this 
loam filling with such effect as to render corking unnecessary. 
But he was careful to have tight joints before battening. 

The " covering " of liquor of one leach should in quantity 
supply one or two liquors for the layaway. There should 
be no fraction or portion left over. The leaches should 
be made of hemlock or pine plank, not less than two inches 
thick, battoned together and corked. Two days' work will 
make a leach 10 by 10, and one day will cork it. This is 
additional to the preparation of tho ground and the after 
filling with loam. 

Bound leaches are recommended when it is inconvenient to 



62 THE LEATHER MANUFACTURE. 

place them under ground. These are more expensive in the 
first cost, and will la-t hardly more than four years if made 
of hemlock, and five or six if made of pine; but by reason 
of the more rapid action of the sprinkling process it is claimed 
that one-quarter of the leach capacity under that system will 
give the full result of the less active press system, and this 
statement is probably well founded. 

Round leaches may be used on the press principle, but the 
square leach cannot very well be used by the Allen <fc War- 
ren, or sprinkling process, although some attempts of this kind, 
moderately successful, have come to my knowledge. In this 
general statement it is supposed that the reader understands 
the method of making round as well as square leaches, and 
of connecting them, both from above and below, with the junk 
yard, waste conductors, etc.; therefore, mention is made in 
detail only of such points in regard to the connections of the 
press leach as are peculiar to its system of working. 

Let us suppose six leaches all placed on a level, each of 
them having % false bottom, and constructed in the usual way. 
Each of these leaches have a tight conductor leading from 
under the false bottom up to the top of the leach — so tight 
as to prevent the passage of any liquor except such as has 
been through the circuit and down under the false bottom. 
If these tight tubes or conductors are placed in opposite or 
alternate corners of the leach, it will often prevent currents, 
which are likely to form if they are otherwise placed. The 
effect of placing a tight tube in tins position is of course to 
cause that tube to b9 always filled with such liquor only as 
has passed through all the bark, and is equal in strength to 
thai si. mi i ding under the false bottom; it will, besides, stand 
■Hi a level with the liquor in the leach, and will overflow when 
it reaches up to the opening which leads to the next adjoin- 
ing leach. These openings should be about 8 to 10 inches 



THE LEATHER MANUFACTURE. 63 

fir m the top in each, leach, and about 2 inches in diameter ; 
if the openings are oval or oblong, all the better. To prevent 
currents forming it is usual to cover the bark with boards, so 
that the liquor will spread over the whole surface and press 
from the top. But if the system is worked uniformly there 
will be no difficulty from currents forming. It is always safe, 
when the leach is rilled with new bark, to carefully level it off 
and cover the whole surface with boards perforated with inch 
holes, the whole to be battened down, so as to hold the bark 
in place. These board coverings answer the double purpose 
of holding the dry bark from rising (floating) and spreading 
the weak liquor gently over the whole surface. 

Warm water or liquor is more expanded and consequently 
lighter than cold. Strong liquor is heavier than weak liquor. 
Now, if we put the two light conditions together, viz., hot and 
weak, and place them on top of the heavy and cold liquor, 
they will remain separate for all time, or so long as these un- 
equal conditions are maintained. A simple experiment with 
water and tan liquor in a tumbler will demonstrate this prac- 
tical result. Weak tan liquor will stand all day on the top of 
strong and heavy liquor, if not agitated. Now, if to the weak 
liquor we add heat, the separation will be still more marked. 
A tumbler half filled with weak and warm liquor may be 
forced out of the top by gently inserting strong and cold 
liquor underneath by means of a pipe. The action of these 
bodies, if the experiment is carefully made, will satisfy any 
one that the system of press leaching can be carried on with- 
out mixing the liquors on their passage, if the system here 
recommended is followed. 

The six leaches should at all times be, equally, from two- 
thirds to three-quarters full of bark, and stand covered 
with liquor varying in strength with the strength of bark in 
each. Let us suppose that the head leach has just been filled 



g 4 THE LEATHER MANUFACTURE. 

with fresh ground bark; the last or back leach is then full of 
spent tau ready to pitch, and the intermediate four leaches 
are divided both as to strength of liquor and age of bark from 
these two points. No liquor is sent into the yard except 
from the top of the head leach, and where very strong liquors 
are needed only one liquor is so sent from each head leach, so 
that the accumulated strength of all the bark in one leach is 
concentrated in this one liquor. If a less degree of strength 
is required, then two runs may be taken off, and m excep- 
tional cases even three or four. The liquor thus sent into 
the yard is not returned until all the strength is taken from 
it, and is then either sent off into the stream as worthless or 
sent again to the back leach after passing through the heater, 
and heating up to 100° or 120° of heat. The spent liquor, 
with its accumulated acid, should go hack again into the 
leaches for further use if the tanner is making sole leather, 
and should go of into the stream if light leather, such as 
calf, lap, or even harness, is to be tanned. 

If this system is carried out each layer or particle of bark 
must be washed as many times as the whole bulk exceeds th 3 
number of these particles or layers. Suppose the leach to be 
six feet deep, and to be filled four feet with bark. If the cov- 
ering of liquor is represented by the remaining Wo feet (prac- 
tically it will be more than this), then each layer of an inch 
will have these two feet of water pass through its particles by 
corresponding portions of this liquor. So that, in fact, the 
number of times each particle of bark is washed by the liquor 
on its passage is almost infinite. This liquor gathers strength 
nil the way on its passage, both theoretically and practically, 
as banners may demonstrate by taking samples from any 
stage of the progress. If the press is properly worked the 
result will be the same as if six leaches were placed on the 
top of each other, and the whole amount of liquor percolated 



THE LEATHER MANUFACTURE. 65 

through all, or the same as if the bark was leached in one 
leach 36 feet deep. 

One of the advantages of leaching by column in this way, 
rather than by percolation or flooding, is that currents are 
not so likely to form, and the fine bark dust is not forced to 
the bottom to stop the free passage of the liquor. Currents 
are more liable to form with any other known mode of pass- 
ing liquor through bark than by this method. 

While the writer regards six as the proper number of 
leaches to connect in one set, as many as twenty-four are 
sometimes so connected ; but when so many are connected it 
necessitates the use of pumps to aid the press by more or less 
forcing of the liquors. Covering so much space, with so small 
a v iriation in the weight of liquor in the leaches, necessarily 
makes the flow sluggish. 

In regard to the Allen & Warren leach, perhaps the fairest 
way to present its merits would be to give extensive eTitracts 
from the patentees' published circulars. But this would 
carry me far beyond my purpose, which is to indicate in the 
fewest words the conceded merits of the various methods of 
leaching. In this view, it would be unfair to hold this patent 
accountable for all the damage done by those who use it. 
There is no reason why hot liquor or water should be per- 
colated through newly-ground bark, as is the custom of many 
tanners who use this leach. Nor is there any necessity for 
running into the yard the fine dust and sediment which 
naturally runs off with the liquor through the open lattice 
bottom. Both of these practices are rather an abuse of the 
system, which may be avoided. Cold liquor can be used on 
the new bark by this process as well as any other. This 
should, to follow the principle of the press ]each, bo the 
strongest liquor at the disposal of the tanner. If, for in- 
stance, a liquor of 16° by the barkometer is run on through 



HO THE LEATHER MANUFACTURE. 

the sprinkler, it should turn off a liquor of double that 
strength. 

The patentees of this form of leach have laid d >wn certain 
formulas and claim results which are not usually attained 
by tanners, and which the writer is inclined to think are not 
realized in practice. Their claims, then, which are based on 
superior results over any other system, are not realized. No 
(aimer can get more strength than all there is, and there are 
several methods which practically accomplish this. 

This sprinkler leach does concentrate liquor more than 
any other system, as it is worked, i. e., a given or limited 
quantity of water will carry off more tannin by this process 
than by any other. In still other words, the tanner can con- 
trol his strength better by this method than by any other. 
For instance, the first barrel or hogshead of liquor which 
percolates through may stand as high as 32° to 36°, and 
then the strength begins to decrease, so that when the bull: 
of the leach has run off the whole aggregate strength may 
not be over 14° to 16°. The tanner may stop at any point 
during this percolating process, and thus secure just as little 
bulk and just as much strength as he desires. There are 
many forms of this leach, and as many methods of econom- 
ically working them. The newly patented form (the Mc- 
Kenzie patent) now so successfully making extract at Yan- 
dalia, N. Y., is one which is claimed to be very economical 
The leaches in this case are round, and only about three 

i deep, and are movable. The whole leach, when filled 

I h newly ground bark, is placed under two others of like 
size. The percolation continues through each until the new 

■ k is reached. It is claimed that these filled leaches are 
handled by machinery so economically that one man, or even 
ii boy, can empty and replace a leach without difficulty. The 

(del indicates great ingenuity and effectiveness, but whether 



THE LEATHER MANUFACTURE. 67 

the saving of labor will overcome the disadvantages of cost 
must be determined hereafter. 

The writer once tried a series of experiments on construct- 
ing leaches that should revolve, and while he had no diffi- 
culty in perfectly leaching the bark, he very much doubted 
whether the saving of labor was a sufficient compensation for 
the cost. The general plan consisted in making a leach eight 
feet square by two feet deep. This would, when constructed, 
make an inclosure which would hold one cord of ground 
bark, weighing about 5,500 pounds when wet, independ- 
ent of the weight of the leach. This leach was hung by 
an iron gudgeon firmly screwed to the center of the flat 
sides or strong timber framework of the leach. On these 
gudgeons rested and turned this immense box or leach. Two 
of the ends were perforated full of fine holes, through which 
water or liquor was run or percolated for a limited time, and 
then by reversing the leach all the bark which had been 
packed would be loosened up, and the further percolation 
could be continued. The final pitching or casting of this 
leach was effected by opening a large trap door, which would 
allow all the bark to drop on the floor below, or it could be 
directed off into the stream by a shute. Six hours of active 
operation with this leach sufficed to take all the tannin from 
the bark. One of these small leaches would in twenty-four 
hours leach four cords of bark, with very little labor. But 
there is considerable machinery and wear and tear to this or 
any other kind of detached leach, and while they may be suc- 
cessful theoretically, practically the writer canuot commend 
their use, with his present experience. 



CHAPTEE VII. 
HANDLING. 

THE HAND REEL— THE BOOTEE HANDLER— ITS CONSTRUCTION AND OPEBA- 
rnON— IMMEBSED DRUM WHEELS— A METHOD OF RAISING HIDES FROM 
THE HANDLER VATS— THE TUB WHEEL HANDLER— HANGING HIDES IN 
THE HANDLERS— THE " ENGLAND" WHEEL— HANDLING WITH THE CON 
ROLLERS. 

Passing by for the present the direct effect of the process 
of handling on the leather, in this chapter will be considered 
merely the manipulation of the stock, with reference to the 
amount of labor required, and the most approved methods 
for doing the best work at the least expense. 

In no department of the tanners' art is the practice of dif- 
ferent establishments more varied than in the matter of 
handling. Patents and improvements, almost without num- 
ber, have from time to time been pressed upon the attention 
of tanners, and the methods of handling are to-day as varied 
almost as the tanneries are numerous. 

Commencing with the old plan of "hauling up" by hand, 
throwing on packs, and allowing the sides to press and drain 
for a portion of each day — or the still more modern practice 
of "shifting" over from one vat to another — we have of late 
years adopted mechanical appliances which make this labor 
l.ss a drudgery, and less exacting on the muscles of the arms, 
back and legs. The most generally approved methods are a 
"hand reel" and the "rocker handler." The hand reel is a 



THE LEATHEE MANUFACTURE. 69 

revolving skeleton drum, which is made to turn on the top of 
a stand or frame elevated about three feet above the top of 
the vats. Both wheel and frame are light and portable, so 
that two men can easily remove them from one location to 
another, over the t ps of the different vats. The reel is 
placed on the alley-ways between the vats to be shifted, and 
the sides, hides or skins to be transferred, being tied to- 
gether, are drawn over from one vat to the other by means 
of this revolving drum. One man is required to turn the 
crank and another to adjust the sides or hides in the head 
vat. By actual count it requires four minutes for two men to 
perfectly transfer 150 sides from one vat to another, and the 
labor is made as easy as the old method is fatiguing. Two 
men will average a pack every eight minutes during the day, 
including; the transfer of the reel. 

The "rocker" handler consists of a frame set in the top of 
the vats, constructed of wood. This frame should fill the 
vat within two inches on the ends, and one inch on tiie sides, 
so that when it rocks from the center it will play without 
touching. It should be made of two-inch plank and the 
frame should be of stuff 2 by 6 inches in substance. The 
end pieces should be of hard wood, not easily split, since 
they must bear the strain of the whole pack. The side pieces 
may be of pine or hemlock, but where hard wood is at hand 
it is best to use that for the whole frame. The center of the 
frame rests on pivots or steps, supported by uprights from 
the bottom of the vat. A "stop" at each end of the vat limits 
the rocker from vibrating up and down more than about eight 
inches. It is not intended to make any of these suggestions 
arbitrary as to construction or working, but a little thought 
at the beginning as to the most durable construction will save 
much repairing in the course of years. 

The sides are attached alternately by the head and tail to 



70 THE LEATHER MANUFACTURE. 

the cross pieces, backs up and bellies down, by means of 
hard wood pins, permanently fastened into the head frame 
pieces. Usually one end is fastened directly to or over the 
pin, and the other by an adjustable string, which may be not 
over a foot long, and may, by a permanent slipping noose, be 
used continuously. 

[In the illustrations given on subsequent pages will be 
found good representations of both the "hand reel" and 
:< rocker handler," from which their construction and the 
manner of operating them will be easily understood.] 

This " rocker handler " will, also, in the next chapter, be 
commended over any or all other methods for making plump 
shoulders and offal, as well as for general economy. 

Besides these two kinds of handlers now in general use 
i tli e latter in the lime and the former in the sweat leather 
tanneries), the tanners in and around Baltimore, Md., use a 
lattice drum fully immersed in the liquor ; from the outside 
or circumference of this wheel or drum the sides are sus- 
pended, attached alternately by the head and tail. One 
method is to attach the leather to the outside, but the sides 
are generally suspended on the inside of the wheel or drum. 
In the first case the sides are reeled over the outside of the 
drum, falling in folds, much as the top of an umbrella comes 
together when put down, and those who use this method 
claiiii as an advantage that the liquor is pressed out in the 
process of turning and reeling up on the drum. But, as an 
objection to both of these plans, it maybe said that they 
.Ion-ate the grain transversely, and make thin backs and 
thick offal. This effect is more noticeable if the leather is 
fully tanned in this manner, without being taken from the 
i iriginal vat in which it enters. If these immersed drum reels 
used only as handlers, as is the case with the rocker, 
then perhaps the effects spoken of would not be so notice- 



THE LEATHER MANUFACTURE. 71 

able ; but so observable are these defects now, that there is 
no difficulty in distinguishing leather tanned by this manip- 
ulation from all others, by the long grain transversely follow- 
ing the line of the back. 

The liquors are pressed around to strengthen up the vats 
into which these revolving drums are used. The principle 
of the press in the case of these yard vats is not unlike the 
press of the leach already noticed in Chapter VI. ; indeed, 
the same practice brings about the same result. Of course 
no agitation of the liquor is permitted while the press is in 
progress, otherwise the liquor would mix and destroy the 
principle of the action. 

A most economical and efficient method of facilitating the 
raising and transfer of packs laid away in bark is effected ia 
the following manner: Alight frame made of plank is laid 
on the top of the liquor before commencing to lay away a 
pack. At the outset it floats on the liquor, but gradually 
sinks as the sides are laid on and "barked away;" when the 
sides are all in, the framework is at the bottom of the pack. 

To each corner of this frame should have been perma- 
nently fastened a half-inch rope as long as the vat is deep. 
The loose ends of these ropes may float on an attached piece 
of wood, or may be fastened to the corner of the vat. When 
the pack is to be raised, the men, standing at each end of 
the vat with one of these ropes in each hand, together raise 
the whole pack to the surface, and when so raised they be- 
lay the ropes around iron bolts or wooden pegs, which arc 
temporarily fastened at the corners of the vat. After they 
have reached down and removed say eight or ten sides from 
the top (all that they could readily reach without the aid of a 
hook), then they again raise the pack, and so continue until 
all the sides are thrown upon the pile, or shifted over to the 
next vat; but usually it is found convenient to pile the pack 



72 THE LEATHER MANUFACTURE. 

up on the adjoining vat, and lay away in the same vat from 
which the sides were taken. 

The philosophy of this practice consists in taking advant- 
age of the law of specific gravity. A side of leather will 
weigh less ounces under water than pounds out, and hence 
it is that two men can easily lift a pack while fully immersed 
in water or liquor, when they could hardly lift ten sides if 
surrounded by air. This system is more expeditious, is much 
easier for the men, and withal saves all opportunity for hook 
marks. Will harness and grain leather manufacturers please 
take notice of this latter advantage ? 

There is still another form of handler which, by way of des- 
ignation, may be called the tub wheel or drum. It was first 
used at Sparrowbush, N. Y., in 1860, and consists of a large 
drum fully eight feet in diameter, and the width of the vat. 
This wheel revolves on a center shaft or flange and gudgeon, 
resting on the top of the vat. Nearly one half of this wheel 
is immersed under the liquor of the vat, and the remainder 
is, of course, out of the liquor. The stock is thrown in at a 
side trap door, and revolved inside this wheel until colored or 
ready to go into the layaways. Projecting wooden j)ins from 
the inside surface separate and carry around the stock. A 
more recent improvement on this wheel is to divide it off 
into four segments or sections, and thus make the compart- 
ments smaller. It is claimed for this improvement that the 
wheel turns easier, as a portion of the contents is always 
held near the center, and only goes to the circumference a 
portion at a time. Besides, a Swiss calfskin tanner told the 
writer that it was within his experience that the large wheel 
without partitions was too severe on green stock. He was 
probably right, for such violent action is apt to "purge" 
stock" when it is green and the liquors are weak, as they al- 
ways must be in the earlier process. 



THE LEATHER MANUFACTURE. 73 

The hanging of sides, hides or skins over cross sticks held 
up by lateral supports in the vat, and the agitation of the 
liquor by plunging, is a most economical method of hand- 
ling, and one that should be resorted to by all tanners who 
cannot conveniently adopt the rockers., The " strengthening 
up " may be effected by drawing off say one-quarter or one- 
third of the contents of the vat, and replacing by stronger 
liquor. The gentle agitation of the fiber and the exposure of 
the full surface of both grain and flesh to the action of liquor 
is essential to a proper handling process, and so long as this 
can be effected, no matter whether by manual or mechanical 
methods, it is all the same in effect. 

The process which has for so long a time been improperly 
attributed to Mr. England, and known as the "England 
wheel" method, has very general acceptance by many light 
leather tanners. In this method of handling the wheel re- 
volves on the top of the vat, and is constructed in skeleton 
form, with buckets or paddles, which, when turned, dip about 
six inches in the liquor, causing a thorough and constant agi- 
tation of the contents of the vat. If the vat is square in the 
bottom there will be a great agitation, and it will answer im- 
perfectly the purpose, but to make the liquor and the stock 
contained in the vat revolve at the same time with the greatest 
facility, the bottom of the vat should be circular, but not lat- 
ticed, as was contemplated by the patent of Mr. England. 

This description of a circular-bottomed vat with a revolving 
wheel in the top had its origin in the city of Brooklyn about 
the year 1840 ; but circulating or handling vats, in a modified 
form, were well known in Germany long before they were in- 
troduced here. For the coloring of sheep, calf, kip, light 
upper or splits, this wheel and circular-bottomed vat is most 
serviceable, but when applied to the after process of tanning, 
as has been attempted, especially in heavy leathers, must al- 



X THE LEATHER MANUFACTURE. 



i I 



ways result in failure, according to the experience of the 

writer. 

Mechanical power should always be introduced into the 
handling yard. All the mechanical appliances which have 
been mentioned are capable of being operated by shafting, 
pulleys and belting. The "rockers" and "skeleton drums," 
particularly, should be driven by power, which may be ac- 
complished by allowing a shaft to run overhead and between 
each tier of vats. An "eccentric" or "crank" motion can 
easily be geared from a shaft, as all mechanics understand. 

The writer has not called attention to several attempts to 
raise whole packs, both in the handlers and also in the lay- 
aways, by mechanical power, because they are generally ex- 
pensive and ineffectual methods of handling. 

Perhaps this list of handlers would not be complete with- 
out including the patented rollers of a Mr. Cos, of London, 
which were brought to this country about the year 1840, and 
were adopted only in one or, at most, two yards, but, as they 
were in quite extensive use in some portions of Great Britain, 
they deserve this mention. The rollers are made of wood, 
and are covered with cloth or matting; two rollers, about 
two feet in diameter each, are made to revolve with their 
surfaces so close together as to draw the side through and 
squeeze out the spent liquor, which, according to the theory 
of this patentee, has deposited its tannin, and should be dis- 
placed to give opportunity for new and freshly charged ooze 
to come in contact with the gelatine of the hide. The sides 
or butts are tied together in such way as to make a contin- 
uous belt, and by means of these compressing rollers are 
drawn from one vat and dropped over into the next. 

The effect of this frequent compressing of the fiber is to 
make the leather thin and hard. The writer has seen some 
very he&vy weighing leather made by these rollers, but as the 



THE LEATHER MANUFACTURE. 75 

system contemplated and used much stronger liquor than it 
was usual for our tanners to employ at that time, to this cause 
was attributed the wonderful resulting gain. In the first ex- 
periment with these rollers at one of the tanneries in this 
country 194 pounds of leather were made from 100 pounds of 
dry Buenos A) res hides, but the rollers were so expensive 
that they have long since gone into disuse here, and meas- 
urably so in England ; yet it must be confessed that for butts, 
bends and trimmed leather, it is much better suited than to 
our sides, and to supply a demand for firm and even hard 
leather, as is required in Great Britain, these rollers may 
serve a useful purpose. 

So long ago as the year 1842 the writer saw at Wobum, 
Mass., a process of handling upper leather on frames, immersed 
in the vats, which at that early day presented a foreshadowing 
of the more modern and better process of rocking the hand- 
lers. But even yet the stationary sticks or frames are in use 
by pebble and grain leather tanners in several large tanneries. 
This successful practice only demonstrates what the writer 
has repeatedly had occasion to say, viz., any method by 
which the fiber is gently agitated and the whole surface ex- 
posed to the liquors will answer the purpose contemplated. 



CHAPTER VIII- 
HANDLING AND PLUMPING. 

WHICH MAY BK USED ITS EEE h^erS-DUT- 



THEE- 



The treatment of sole leather is so different from that of 
upp er, harness, etc., in the preliminary or handling process, 
21 Rework on these two classes of stock will be consid- 

ered separately. ,. 

It has become of late years qnite universal to make a 
Motion between "acid" and "non-acid" treatment ^pre- 
paring hides to be tanned into sole leather. These terms 
though in common use, do not convey an accurate idea of 
the differences in the process. No sole leather is prepared 
for the yard without the use of acid of some kind, but what 
is meant by the term "non-acid" is, that only gallic acid 
coming from bark liquor is used in the one case, and in the 
other sulphuric acid or vitriol isemployed. This employment 
£ ritriol as a means of plumping the fiber of the hide is of quite 
recent date in this country. In Great Britain the distinction 
has been maintained tor a long time between "vitriol butts 
i bends and those that are not raised by this process. As 
early as 1853 the writer commenced the use of vitriol m the 



THE LEATHEK MANUFACTURE. 77 

preparation of "union crop" leather. But this was on 
limed stock, and in very moderate quantities. The mineral 
acid was used quite as much to counteract and neutralize the 
lime as to plump the fiber. When used to this limited extent 
the " buff" was not iojured, the grain was plumped, and the 
whole structure of the hide slightly swelled. But from this 
small and cautious beginning the use of vitriol extended until 
the sweat leather tanners took it up, and from about 1860 to 
the present time it has come into general use. 

If this practice had been intelligently and openly intro- 
duced, far less damage .would have resulted ; but each tanner, 
depending upon his own judgment, and, it must be confessed, 
on very limited information, has gone on blunderiiDg, all the 
time thinking himself much wiser and more skillful than his 
neighbor, until vitriol-raised leather has come to receive the 
condemnation of all of our best manufacturers. Certainly it 
is discredited by all who have regard to the appearance of 
the bottoms of their boots and shoes. 

For several years after the first introduction of the new 
practice the fact of the use of vitriol was kept a secret, and 
was not exposed until the general quality of our sweat leather 
had deteriorated to such an extent as to cause alarm. 
Now the proper use of this acid is better understood, and the 
early abuses in its application are measurably avoided ; but 
even to this day many otherwise good tannages are injured 
by the improper use of vitriol in the handlers. In this, as in 
all other innovations, there should be more frankness among 
the tanning fraternity ; its members should learn that ignor- 
ance and bad workmanship reflect finally as much on the in- 
nocent as on those who are more directly responsible. A 
tanner who makes poor leather, particularly if tho defects 
are latent and not at once discernible, unfavorably influences 
the whole trade. 



78 THE LEATHER MANUFACTURE. 

The writer would gladly impart such information in regard 
to the proper and permissible use of vitriol as would help 
tinners to avoid the defects complained of, but the circum- 
stances under which this acid is employed are so varied that 
any general formula or direction for its use would be almost 
certain to mislead some of those who might wish to be guided 
thereby. Hides are not all of the same specific nature ; some 
will bear more acid than others. Thick hides will bear more 
than thin ones ; steers more than cows ; the butts more than 
the bellies of the same hide. The consequence is that when 
our American sweat leather tanners use vitriol on hides 
worked in without proper classification, and without trim- 
ming, they are apt to overdo the thin sides or thin portions 
of the thick ones. There is no way to avoid this difficulty 
without taking care only to strike the thin portions fairly 
through and then stop, leaving the butt only partially im- 
pregnated. 

In regard to the experience and practice of our sweat lea- 
ther tanners in the use of vitriol — some color their sides be- 
fore they introduce them to the acid ; others use the acid first 
and color last, while still others, and probably the majority, 
use both agents at the same time — they color while they 
plump — i. e., they use the acid in the coloring handlers, and 
strengthen up the handler as each new pack goes in, with 
new, sweet, highly colored liquor and vitriol. 

How much vitriol may be used with each pack? This 
question is often asked, but can never be definitely answered 
without a knowledge of the hides, and of other circum- 
stances. It must depend upon how much the previous 
pack has taken up; how strong the acid is; how heavy 
the sides are; how fully the leather is allowed to carry off 
the acid, etc. There will be no difficulty experienced if tan- 
ners will regard vitriol plumping as a tawing process. If they 



THE LEATHER MANUFACTURE. 79 

will cut the thin portions of the sides, and examine in a strong 
light, they will notice just the extent to which the acid has 
penetrated ; the progress is as clearly defined, although not 
quite so plainly marked, as if the tan liquor itself had been 
present. 

Yitriol preserves the hide, and holds, when combined with 
salt, the gelatine from decay. All the green sheepskin pelts 
that come from England to this country in casks are pre- 
served by this process, and may be so held without damage 
for years. When these skins come, however, to be tanned, 
the acid must be neutralized before they go into the liquor, 
or while in the liquor, otherwise a result is produced just such 
as we see in much of our acid sole leather. A sheepskin 
tanned without neutralizing the acid will swell to more than 
double its wonted thickness, and will tear as easily as brown 
paper of the same substance, while the whole structure as- 
sumes a dark brown hue, which grows darker as it is exposed 
to the air. From this fact tanners may take a hint, as the 
writer has done. Indeed, from some early experience in tan- 
ning what are termed "salted" sheepskins, much of my early 
knowledge of the use of vitriol was obtained. 

Yitriol distends and injures the fiber, and if not re- 
moved from the grain will deposit immediately underneath it 
a dark brown strata, which is most objectionable to manuf ic- 
turers who use buffing wheels instead of hand labor in re- 
moving the grain on the soles of boots and shoes. 

In my judgment, vitriol should never be used to raise 
purely sweat stock. For hides prepared with lime we all 
know that vitriol to a limited extent may be used without 
material damage. What, then, is to be done? All sides as 
they come from the sweats should be thrown into a lime, and 
there handled until they fairly begin to feel its effects, Bay, 
ordinarily, about six or eight hours. The lime will, in this 



SO THE LEATHER MANUFACTURE. 

time, sufficiently penetrate the surfaces to neutralize the acid 
when the sides reach the handlers. Thus treated the dark 
strata will be either entirely removed, or so far modified as 
to be less objectionable, depending on the strength of the 
lime and vitriol used and their relative proportions. 

It should be remembered that sole leather raised with 
gallic acid (if the acid be strong) will leave a modified dark 
strata, but this is controllable by other acids, which the boot 
and shoe manufacturers employ in " cleaning up their bot- 
toms." No counteracting agent has yet been found, however, 
for the vitriol stain, and the exposure to the atmosphere of 
leather thus affected increases its unsightly appearance. 

The German-tanned "warm-sweat" sole leather has the 
difficulty here complained of to a more marked and objection- 
able extent even than our own tannages ; but as the consumers 
there care less for the buff than we do, this defect seems to be 
disregarded. They use vitriol or acid liquors even to a greater 
de<n-ee than we do, and to such an extent indeed that most o' 
their sweat sole leather will crack and even break by close 
folding. Consumers of leather in Continental Europe, hav- 
ing been accustomed to this defect in their own home supply, 
make less objection to it in us than do the manufacturers of 
Great Britain. The tanners of Great Britain do not sweat, 
either by "cold" or "warm" process, and hence they use 
vitriol and lime jointly, with less damaging effect. 

It is proper here to say that in France, Germany and Swit- 
zerland women's sole leather and all the light leathers are 
limed, as in Great Britain, and this "cracking" and "old 
hatty" appearance of the fiber is confined to the sweat vitriol 
and acid raised sole leather, which are greatly inferior to 
their other tannages. 

Vitriol-raised leather, when treated in the after process 
with weak liquors, produces a most unsatisfactory result. 



THE LEATHER MANUFACTURE. 81 

Tlie grain is poor, the fiber coarse and hatty. No attempt is 
here made to solve the mooted question whether vitriol does 
not destroy the tannin. It is conceded that it will plump and 
hold the fiber, and will facilitate the tanning, but whether 
these advantages, in an economical point of view, are not 
more than overbalanced by its distinctive action on both fiber 
and the tannin, must be left for future experience to de- 
termine. 

In closing the suggestions on this point the writer would 
like to say that great care should be exercised in handling 
while in the vitriol vat. If the acid is allowed to settle down 
on the grain, stains will result which will cause a clouded ap- 
pearance that will remain to the end of the tanning process. 
My own judgment is that it will always be serviceable to hang 
the sides on cross sticks and plunge as the most certain 
method of distributing the effects of the acid uniformly. In 
adding vitriol to the pack, be sure to put it in before the 
sides go in, and plunge thoroughly, otherwise the acid will 
drop down and discolor the grain. The specific gravity of 
vitriol being much heavier than that of tan liquor, its tend- 
ency is to settle, and unless great care is taken it will so 
settle and mottle the grain of the pack. 

In preparing hides for sole leather by the lining process, 
if only so much lime is allowed to permeate the fiber as to 
enable the tanner to remove the hair, as has been already 
indicated, distinct bating is unnecessary. If the hide is 
filled and swelled with lime, the treatment should be such 
as to remove such excess of lime before the sides come to the 
handler. But, usually, if the sides are wheeled in warm 
water for ten or fifteen minutes, they will be sufficiently 
cleansed to enter the handler. 

The first handler liquor should be the oldest and most 
worthless liquor in the yard, so worthless that after handling 

6 



82 THE LEATHER MANUFACTURE. 

the green pack in it for a few hours it can be run off in the 
stream or sent again to the back leach.* 

The pack, after being thus cleansed, so far as this old spent 
liquor will do so, takes its place in the order of succession in 
the handlers. If, as is assumed, the rocker system of hand- 
ling is observed, then it will take the place of the pack which 
has just gone to the layaways, and a liquor is prepared 
specially by pumping the strong liquor found in the vat over 
on the next pack, and so on around until the weakest liquor 
is placed on the new incoming pack ; care should be observed 
to feed each pack with an increasingly strong liquor, not, as 
too many practice, once in each day, but at least twice. 

Far more damage is done by feeding too slow than too 
fast; so long as the old liquors from the layaways are used 
there need be no fear of either feeding the packs too fast or 
too frequently, only let them be fed in their order of entrance. 

Of course, as many packs should go out as come into the 
handlers daily. It will be found profitable to keep each pack 
from ten to twelve days in the handling rockers, or in any 
other method of handling that may be adopted. This time 
will suffice to overcome all the effects of the lime, fairly 
plump the sides, and set them well on their way toward the 
after tanning process. 

As a last parting word on this subject the writer would urge 
tanners to put away from their minds the fear so often ex- 
pressed that liquors may be too strong to start with. If eight 
or ten packs are in the handlers, commencing with the head 



* Just here the writer woul 1 say that, whether this old liquor should go again 

to the back leach or off in the stream will dep3nd very much on the manner of 

[B irs. It', as in tlie tnir system of using the press leach, no liquor is 

flowed to go bach until expended, then the dirty water (for it is little more), 

1 oi tannin, which washes an 1 cleanses each new pack which comes to 

i should be discarded ; but if there shoul 1 remain either gallic acid or 

1 ■''> "'• then it shoul I certainly go to the back leach. Without exer- 

»me discretion in this regard valuable qualities may be thrown away. 



THE LEATHEB MANUFACTURE. 83 

pack and running down to the last one, the best and strong- 
est of the discarded layaway liquors may be used with 
safety. ' These liquors will always contain acid enough to 
prevent the "puckering" or " binding" of the grain. Liquors 
weighing by the barkonieter 16° are none too strong for the 
head handler. So large a proportion of this weight will be 
acid that they may safely be trusted to work no harm. 

The treatment of the lighter tannages, such as upper and 
harness leather, in the handlers, is far different from that of 
the heavy sole leather tannage, just considered. These lea- 
thers are sold by the side or foot, or should be, as no tanner 
can afford to treat his stock as such goods should be treated, 
and then sell it by weight. 

After the lime has been thoroughly removed by a bate of 
hen manure, or wheat bran, or some other depleting process, 
the stock enters the handler, in the first instance just as th« 
sole leather did, but instead of taking a course of old, sour, 
strong liquors, it is only retained long enough in the acid 
liquors to "brighten" and clear the grain, and then weak, 
sweet liquors should be fed to the packs, just in the order 
in which they come from the leaches. These liquors should 
go back to the leaches very frequently, to be " sweetened " 
aud " strengthened " up. Fresh sweet liquors standing from 
10° to 12° should be as strong as is ever permitted in the 
handlers. The " rockers " should be used, however, to plump 
and handle even upper, harness and calf, for, although the 
sweet liquor will prevent that extreme plumpness so desir- 
able in the heavier tannages, a close, round grain will be 
formed, and a degree of fineness and plumpness of the 
shoulders and offal will be secured not attainable by the 
usual manual handling process. 



CHAPTER IX. 
" LAYING AWAY. 

TIME REQUIRED AND STRENGTH OF LIQUOR WHICH SHOULD BE EMPLOYED— 

TANNING IN THE HANDLERS VS. LAYING AWAY EUROPEAN METHODS 

" BLACK ROT " AND WHITE SPOTS THEIR CAUSES AND THE REMEDIES 

SHOULD HIDES BE LAEO AWAY GRAIN UP OR ELESH UP ? MAKING 

WEIGHT LN THE LAST LAYER. 

Proceeding in the order of the successive processes of tan- 
ning, we find our pack coming from the handlers not only 
well " plumped" and uniformly "colored," but fairly "leath- 
ered." The stock has taken upon itself " substance," and a 
reasonable degree of firmness. Supposing that four layers 
will now carry out our tanning and completely fill the fiber, 
we shall assume that the remaining work will be divided into 
the following periods of time, during which four successive 
layers of bark will be given each pack. To the first layer we 
will give ten days, to the second fifteen days, to the third 
twenty days, and to the fourth thirty days, making in all 
seventy-five days. But it must be evident that leather differ- 
ing in substance and weight will considerably vary in its 
requirement of time ; and then, too, much will depend upon 
the season of the year, the strength of liquors applied, and 
other circumstances. If we commence wdth a liquor of 
16° degrees strength with the first layer, and end with 30 D on' 
the fourth layer, seventy-five days will be found ample time 
to tun the heaviest sole leather. 

The writer tried an experiment on one pack of slaughtei 



THE LEATHEE MANUFACTURE. 85 

hides, to test the actual time necessary to tan good middle 
and overweight leather, averaging say 20 pounds per side. 
This experiment, made under his own daily observation, 
enables him to speak with great confidence of the result. 
The hides were bought of the Batchers' Association of the 
City of New York, and weighed 70 pounds each, trimmed 
and cured. One week was consumed in their preparation for 
the bark. They were colored and handled for three days in 
an old sour liquor from the first layers, when they were put 
into a liquor of 20 degrees strength and handled daily, 
"shifting" from one vat to another each day, and receiving- 
just enough added strength to keep the liquor at 20 degrees. 
At no time was the liquor over 22 degrees or under 18 degrees. 
In sixty-one days from the time the sides came luto the hand- 
lers they were taken out not only fairly " struck," but well 
tanned. The color was "fairly good," although not as bright 
as other packs which hacTbeen laid away in the usual manner, 
and had taken fifteen to twenty days more time. The con- 
clusions drawn from that experiment were as follows : 

1. Well cured New York City hides will make 65 pounds 
of leather for every 100 pounds of green cured and trimmed 
hides. 

2. Sixty days in the actual process of tanning, handling 
once each day in suitable liquors, will tan the ordinary middle 
and overweights sole leather. 

3. About one-third more time is required if the leather is 
tanned by being laid away in the usual manner. 

4. The color is both lighter and more uniform when laid 
away than when handled. Besides, the tendency of the sides 
to bag is far less when tanned in the usual way, by laying 
away in bark. 

This experiment, if read by a German, Swiss, French or 
Austrian tanner, will be regarded as extraordinary, but an 



86 THE LEATHER MANUFACTURE. 

account of it is given here, not because it is exceptional in 
this country — for many better .results have been attained — 
1 lut for the purpose of bringing into contrast our methods of 
tanning as compared with those of the Continent of Europe, 
for in all statements affecting results the writer must be 
understood as drawing a clear distinction between the pro- 
cesses in Great Britain and those of the Continent. 

It is not claimed that these results are practically secured 
in all instances, or even in a majority of cases in this coun- 
try, for the causes of detention which go to make the aver- 
age time and results are but too well known. These causes 
of delay will be considered in their appropriate place, but 
theoretically our system accomplishes all that is here claimed. 

As possibly these statements may be read by tanners over 
the sea, for their information, as well as for the instruction 
of our own tanners, it may be said that our universal custom 
of leaching new bark and using the decoction obtained for our 
tanning agent, is not practiced to any extent by tanners in 
Continental Europe. They color their green packs in hand- 
lers made from the old sour liquors, which are pumped from 
the layaways, adding (as is the custom of some) a few bas- 
kets of "spruce" bark. The hides, in small yards that are 
run without power, are "poled" in the vat every hour, and 
onoe or twice each day the stock is handled up. But while 
3-et quite "green" and "pulpy" the packs are laid away in 
outdoor round tubs or vats, from eight to twelve feet deep, 
and from six to ten feet in diameter. * 

The first layer is made of old, partially-spent tan, laid fully 
one inch thick on either side of a hid 1 or skin, and well 
stamped down. When the vat is finally filled with these 
alternate layers of bark and green pelts, water is run in to fill 
the interstices. The acid of the bark preserves the gelatine, 
and at the same time neutralizes any lime which may have 



THE LEATHER MANUFACTURE. 87 

been left from the handlers. After twenty or thirty days' 
'time this stock is raised, the bark " skimmed out," and the 
pack relaid. To the old a portion of new bark is added, 
and at each subsequent "shift" or "turn" of the pack 
more new bark is added, all the time holding the old acid 
liquor which has accumulated. 

The writer was informed that in most instances from 
sixteen to twenty months are occupied in these layers before 
the leather is finally declared tanned, and the statement may 
be fully credited, for in no instance, among the numerous 
tanneries visited, did he see any attempt to leach new bark ; 
such leaching as was attempted was confined to the old, spent 
bark, that had been literally worn out by frequent handling. 
This process is slightly varied with calf and upper in the 
handlers and layaways, but substantially the same system is 
followed out in all their tanning. Perhaps, in justice to a 
few large calfskin tanners — notably so in the case of M. 
Mercier, at Lausanne, Switzerland — it should be said that 
much more vigor and a greatly improved system was em- 
ployed. This will be more fully mentioned in the chapters 
on calfskin tannages, in another place. 

The writer hesitates to state the methods employed in 
Great Britain, for the tanning agents there used are so en- 
tirely different from our own that comparisons are impossible, 
and might, if given, be misunderstood. They use decoctions 
quite as strong, in fact, as we do, and much stronger, meas- 
ured by the test of the barkometer, while the time in which 
they tan is very nearly or quite equal to that made by our 
best tanners. If they take longer (as many of them do), as 
much even as ten nvmths, it is on heavy South American 
hides, made into butts and bends that are very stout in sub- 
stance and extremely fine in texture. But native sole leather 
hides, also upper and kip leather, from both native and foreign 



88 THE LEATHER MANUFACTURE. 

hides, are "put through" quite within our best time, and in 
the most artistic way. American tanners can learn much 
from the economies practiced and results produced by the 
tanners of Great Britain, for they do manage to make ex- 
ceedingly good leather from very small quantities of tan- 
ning material, whether native or foreign. 

To return from this necessary digression our methods of 
laying away will now be given with more minuteness. More 
than forty years has passed since the "kiffing" away process 
was given up, and leaching and bark liquors introduced in its 
stead. Few men are old enough to remember when at Salem, 
Danvers and Cummington, Mass., water was used instead of 
liquor in the layaways for sole leather tanning. At present, 
the bark liquor used in the layaways is depended upon to do 
the tanning, and not the interlying bark at all. 

The general usage now is to run the strongest and newest 
liquor direct from the leaches upon the head packs of the 
last layer. These liquors should weigh by the barkometer 
fully 30 degrees of strength. After 30 days' use they will be 
reduced to 24 degrees. A portion of this indicated strength 
is acid. Twenty days' further use on the third layer will 
reduce the strength to 18 degrees, and thus down step by 
step until a large portion of the strength will be acid and not 
tannin, when the liquors will be put on the first layaways, 
or may be run into the handlers and fully exhausted. 

This is not, it is true, an invariable custom, for too few of 
our tanners have anything that may be called uniform 
methods, but the general leaching of bark and the use of the 
graded decoction on the packs, in the order of their coming 
in and going out of the yard, must be conceded to be our com- 
mon practice, and to this extent the system is exclusively 
American and English. 

The manner of running liquors from the leaches to the yard 



THE LEATHER MANUFACTURE. 89 

lr by covered, inclosed wooden tubes or bored-out logs, either 
under ground or under covered ways. The method of con- 
struction and cost of these will be stated hereafter, but where 
heat is used on the head leach, these liquors are too often 
sent into the yard warm, or even hot, and when thus used, 
very much injury to both color aud buff is the result. Yet, 
as Ihese head or strong liquors are, or should be, confined to 
the head or nearly tanned packs, positive damage to the gel- 
atine of the hide does not follow to the extent which would 
be supposed ; while if these warm liquors, from mistake or 
ignorance, go to the half-tanned or green packs, "black rot" 
is almost sure to result, particularly in the summer season. 
The damage is caused by the decay of the animal fiber — ac- 
tual decomposition of the untanned or raw hide. The ex- 
ternal appearance of this damage appears as a sinking in of 
the two surfaces, caused by a general disturbance of the cen- 
tral tissues. When the decomposition proceeds still further, 
and the surfaces break, partially tanned "puss" exudes. 
This disturbance and damage has been popularly denomina- 
ted the " black rot," because, upon the grain side, in addition 
to the " falling away " appearance spoken of, the surface turns 
black, showing dark or black spots wherever this damage oc- 
curs, and this is generally in the thickest and best portion of 
the hide. 

While on this subject of latent defects and damage, perhaps 
it is as well to state the experience of our tanners in regard 
to the "white spots," of which there has been so much reason 
to complain, and which, even with our conceded ability to 
remedy, still cause great depreciation of value in much of 
our sole leather. This defect occurs from imperfect beam 
work. In the sweating process the hides arc soaked, milled 
and sweated within a week, and when the atmosphere of the 
sweats and the nature of the hides favor, the hair " comes" 



90 THE LEATHER MANUFACTURE. 

quite freely; as that fact, under our process, indicates that 
all lias been done that is necessary, the stock is turned into 
the liquor, when, in fact, the workman has never touched 
much of the grain surface of the hide, thus leaving mucus 
and grease. Often the grain has been saturated with the 
greasy substances of the animal, which are not overcome or 
worked off by the beam hand, but remain to resist the action 
of the liquor. Some tanners call this " mucus," but the 
greasy substance which causes this white spot is different 
from mucus, as will be demonstrated by a little examination. 

The New York leather trade, several years ago, offered a 
reward to any tanner who would discover a remedy for this 
defect, and a Mr. Edson came forward with a solution of the 
difficulty. He discovered that potash, soda ash, or any 
strong alkali, applied to this untanned or uncolored white 
spot, would at once make the grain take the coloring matter, 
and subsequently receive the tannin. This was a perfect 
remedy, and led, as any one may perceive, to the cause of 
the trouble. Whereas other tanners ascertained that rubbing 
the surface with pumice stone or brick, or scraping thoroughly 
with a knife, would measurably relieve the damage, the real 
cause of the difficulty was not suggested until the alkali test 
was applied, and then we all comprehended that cjrmse, in 
some form, was the source of the trouble, and, therefore, to 
Mr. Edson was awarded the valuable consideration offered by 
the trade. If, therefore, hereafter, any tanner suffers from 
the appearance of these white spots, and does not apply the 
remedy, he has only himself to blame. These spots may be 
avoided in two ways : First, by thorough working on the 
beam ; or, second, by the use of a strong alkali on the spots 
affected, after the sides have been colored, and the defect 
« omplained of discovered in the handler. 

The best practical method to overcome these spots would, 



THE LEATHER MANUFACTURE. 91 

perhaps, be for the tanner to have a carboy standing in his 
yard with either a strong decoction of sal soda or soda ash, 
from which the attendant on the handlers can take a small 
portion, and by the use of a rag or sponge tonch, and even 
slightly rub, the affected part. It will cause a dark or even 
black stain at first, but this will finally disappear in the after 
process. Some tanners prefer to throw the sides affected on 
a table or beam, and rub or scrape the spots with a smooth 
steel edge ; a round pointed knife is serviceable for this pur- 
purpos-. The latter course can only be pursued, however, 
when the spots are small and infrequent. My judgment is 
that where sufficient care is taken to work fully over the grain 
in the beam house these spots will not be encountered in the 
handlers. 

It is probable that if hard wood ashes, soda ash, or sal 
soda, were freely used in the soaks of such hides as usually 
give this trouble (as, for instance, dry Western and Califor- 
nia), no white spots would ever make their appearance in the 
handle r ; besides, the greasy hides would soak more uni- 
formly. Y/hen a pack of dry hides is thrown into soak in- 
discriminately great injustice is done the " sun dried" and 
greasy portions, from their more persistent resistance of the 
soak. 

The question has often been raised whether the sides 
should be laid grain or flesh up in the layaways. The prac- 
tice is to lay grain "up, and this is justified on the ground 
that, in "hooking up," the grain is not so likely to be scratched 
and marked as it would be if the sides were laid flesh up. 
If, as seems quite likely, the color is seriously affected (par- 
ticularly in hemlock tannages) by the settling of the coloring 
matter on the grain, and a deeper, darker red is the result, 
then tanners may well inquire whether, in their attempt to 
avoid hook marks, they do not entail upon their stock a worse 



92 THE LEATHER MANUFACTURE. 

evil. Besides, it may be asked in this connection whether it 
is not probable that tannin will enter the fiber of the hide 
more naturally from the flesh than from the grain surface. 
The pores of the hide, when on the animal, certainly do open 
their valves outward from the flesh, for all the emanations of 
the animal body go through these outward opening valves or 
pores of the skin, which never receive back from the grain to 
the flesh. "We all know that the goat and sheep skin tanners, 
when they "sew up" their skins, keep the grain outward, 
and tan altogether by pressure from within. But some one 
may ask, Does not the tan liquor surround both surfaces, and 
seek admittance equally from each side? This may be 
answered in the negative, for the heavier or stronger liquor 
settles, and when the sides lie upon each other in layers, both 
the strength and the coloring matter tend to settle downward. 
The theory is that when the tannin comes into contact with 
the gelatine of the hide the union is made instantly, and then, 
if both the hide and tannin are allowed to stand in perfect 
quiescence, the conclusion is drawn that not only does the 
strong liquor settle, but it does its work instantaneously, from 
underneath, while from the top of the side this specific- 
gravity principle of the liquor keeps on acting for a consid- 
erable time, forcing downward the renewed strong liquor, and 
1 (ringing itself into contact with the untanned fiber. This 
may be refining on speculative ideas, but such a theory does 
prevail among some. 

One of these theorizing tanners, within the knowledge of 
the writer, always acted upon this idea, and made it his 
habit, several times each day, to walk over his layaway packs, 
stopping to press his weight forcibly on each as he passed. 
Ho always insisted that by this course he displaced and dis- 
turbed the fixed relation of the liquor to the gelatine of the 
hide, and brought new tannin in contact with the hide. This 



THE LEATHER MANUFACTURE. 93 

we know, that agitation of the fiber and frequent replacement 
of tannin does facilitate the process. 

The last or fourth layer is purposely prolonged, not only 
to fill the fiber and make the leather firm, but also to bright- 
en the color, as is sure to result from the acid liquor, which 
accumulates with age. The fiber is fairly tanned on the 
third layer, but the filling process— the extra weight, indeed 
—is made on this layer, and the tanner who fails to give 
ample time to this last layer must be content with inferior 
solidity and gains. Can leather be overtarmed? Yes. It 
may be so thoroughly tanned as to leave no grain to buff, 
and really no life or elasticity to the fiber. 



CHAPTEE X. 
DEYING AND FINISHING. 

WASHING AND SCRUBBING THE LEATHER THE "HOWARD SCRUBBER "■ — 

WHEEL OR DRUM SCRUBBING DRAINING HOW THE ADMISSION OF 

LIGHT AND AIR SHOULD BE REGULATED IN DRYING DAMPENING 

BEFORE ROLLING THE FIRST AND SECOND ROLLING EFFECT OF 

THE ROLLING ON THE BUFFING QUALITIES BLEACHING WITH SUGAR 

OF LEAD AND SULPHURIC ACID THE WARM SUMAC BATH EFFECT 

OF THE LATTER ON CALFSKINS, GRAIN LEATHER, ETC. 

From the last layer in the yard the finishing process begins. 
If mistakes have been made and defects are apparent it be- 
comes the duty of the finisher to consider and overcome them. 
Where a uniform system prevails, both in the beam house 
and yard, such defects should not be of frequent occurrence ; 
but whatever they are, and wherever they occur, it is the 
duty of those who have charge of the drying and finishing 
loft to make amends, as far as possible. 

The first duty of the finisher is to cleanse the leather from 
all sediment and extraneous matter. This can be better 
begun before the leather has been exposed to the air than 
after such exposure. For this reason the pack should be 
taken in hand immediately on coming from the layer, when 
the leather should be thrown into clean water, or may, if there 
are stains and a mottled condition of the grain, be thrown 
into an old sour liquor, and left for a day or more. We must 
bear in mind the object to be attained, namely, to cleanse and 



THE LEATHER MANUFACTURE. 95 

purify the grain and flesh. This can be done in various 
ways — first, by rinsing and hand scrubbing ; second, by re- 
volving drum wheels, with surfaces covered with splint brooms. 
This method is covered by the patent of Mr. Howard, and 
the scrubbers are known as the "Howard scrubbers." The 
third plan is by a revolving drum wheel, during the revo- 
lutions of which the leather is washed by a constant tumb-r 
ling and turning over in water, which is freely supplied. 
This wheel, in its application to such service, is also covered 
by a patent. The merits of each of these processes will be 
considered in their order, but before presenting the remedy 
for the evils which necessitate this scouring let me consider 
their cause. 

If the liquors are obtained from the press leach there will 
be no sediment or discoloration to remove, and consequently 
nothing more will be required than rinsing and scrubbing 
with a hand broom, or brush. But if the liquors have come 
from the "sprinkler leach," or from the ordinary "flooding 
leach," then 'there will have accumulated bark dust and sed- 
iment, blended with resinous matter, which will attach itself 
to the flesh and grain, and will require mechanical power for 
its removal. 

The " Howard scrubber " is now largely relied upon to re- 
move these defects. It consists of two revolving rollers or 
drums, with their surfaces coming very near together, to 
which are attached brooms or brushes, which quite meet. 
Through these scrubbing surfaces the sides are made to pass 
— sometimes once, but often twice and three times. The 
friction is increased by holding back the side with the hand 
with more or less firmness. Two men can, with this machine, 
pass thiough about 500 sides per day, and do the work well. 

More recently the "wheel " or " drum scrubber " has com • 
into use. This consists of a drum wheel about six to eight 



96 THE LEATHER MANUFACTURE. 

feet in diameter, four or five feet wide, made strong enough 
to resist the hammering process of the revolving sides of 
tanned leather, which are made to " thrash " around in the 
inner surface of the wheel as it revolves slowly, say about 
twenty revolutions per minute. The inner surface of this 
wheel is furnished with pins or projections, which carry the 
sides around with the motion until they are raised sufficiently 
from the bottom to violently agitate the fiber by their drop- 
ping down, and by the friction caused by the sides rubbing 
against each other the surfaces are cleansed, very much on 
the same principle as iron castings are now made smooth by 
being rubbed against each other in a revolving wheel — or as 
shoemakers' pegs are polished by friction and contact — being 
revolved in bulk inside a tank or hogshead. It is claimed 
that the most of the bark sediment or accumulation is re- 
moved by this wheel within five minutes, and as about ten or 
fifteen sides can be thrown in at a time, it will be perceived 
that the cleansing process is rapid and economical. 

Great care, it appears to me, should be observed lest this 
wheeling be continued too long, the effect of which would be 
to pound out the weight and make the leather soft. The 
writer is assured that with care these defects can be avoided. 

"When the sides have been thoroughly cleansed, by means 
of either of the foregoing processes, they are usually laid in 
packs to drain, but in doing this great care should be taken 
to place flesh to flesh and grain to grain, with each side so 
exactly covering the other as not to allow the flesh of one to 
touch the grain of another. Unless this precaution is taken 
the strong liquor, which is absorbed and held by the flesh in 
undue proportion, in spite of all attempts to remove it, will 
impart itself to the grain of the side it comes in contact with, 
if the pack is unevenly spread, so that the drainings can run 
down and stand in small pools on the grain surface. Such 



THE LEATHER MANUFACTURE. 07 

spots will be marked with the stain of the bark liquor when 
the leather is finished. 

The most ready way to avoid the forming of these " cups " 
is to throw the pack over a " half log," cut lengthwise, which 
is made as follows : Saw a hemlock loo - , two feet in diameter, 
through the center ; turn the concave surface up and the flat 
surface on the floor, and lay the pack lengthwise on this stick 
of timber ; it will be almost impossible in this way, with or- 
dinary care, to have any cavities form into which the spent 
liquor will run and cause these stains. 

The pack, while thus exposed to the air, should be covered 
with canvas, to prevent the edges and exposed surfaces from 
meeting the light and air ; otherwise such portions will b( - 
come darkened to such an extent as to show finally great 
discoloration. 

After the pack has been thoroughly drained, a slight coat 
of fish oil should be put on the grain and flesh by a rag, and 
the leather may then be hungup to dry. If the Turret dryer 
is used, or the principle of that dryer is observed in the con- 
struction of the building in which the leather is placed, the 
perfect control of the light and air thus obtained will enable 
the workman to keep all light and any considerable drafts of 
air from the leather for three or four days, or until the sides 
are fairly stiff and dry on the surfaces. After the moisture . 
has been evaporated from the surfaces air may be admitted, 
but not a strong light, for the free admission of light to the 
leather is certain to darken the color. Ten days will dry the 
heaviest sole leather if a proper drying loft is employed, but, 
whatever time is requisite, the leather in all its parts should 
be thoroughly dry before it is taken down. When in this 
condition it may be held subject to the call of the roller. 

Two days at least before the leather is rolled, the " damp- 
ening process " should begin. The sides should be first 



98 THE LEATHER MANUFACTURE. 

sprinkled with water carefully, both on grain and flesh, and 
then laid down, grain to grain, and flesh to flesh, taking care 
as before not to have " cups " form where liquor stains may 
occur. After a period of a few hours the same process may 
be repeated, but with more care, making certain this time 
that all parts have not only been reached, but that no more 
water has been applied than will readily absorb. The pack 
should then be carefully laid in a large wooden box or 
tight room, care being taken to pack snugly, so as to get in 
as many sides as possible, and at the same time to prevent 
the air reaching the skirts to dry and discolor them. 

If the dampening process has been attended to with care, 
the leather will be in condition to "pack" under the roller 
without "rebounding" or " comingback;" but to make sure that 
all the parts are evenly moistened, great care should be taken 
by the attendant to re-sponge both grain and flesh lightly 
In fore the sides are passed to the roller, taking special pains 
to retouch such spots as have lost their moisture, and become 
partially dried. It will also serve a useful purpose to pass 
an oiled rag or sponge over the grain surface, to prevent 
" furring up " under the roller and on the roller bed. The 
leather should be so prepared that the whole fiber will pack 
solid, without being so damp as to induce the soluble portion 
of the coloring matter to press through the grain, as will be 
the case if the leather is rolled when too damp. "We all 
know that snow may be too dry as well as too damp to pack, 
and the same is true of leather. The happy medium should 
always be observed to secure the best result. 

Since our tanners have been trying to meet the tastes and 
wants of the German market, some of them have adopted a 
somewhat different method in finishing vitriol raised leather. 
Duly the grain is dampened, and the residue of the fiber io 

'lied dry, or nearly so. This process gives a fictitious sub- 



THE LEATHER MANUFACTURE. 99 

stance, and a harsh, hard, dry fiber, which seems to corre- 
spond, to the character of the German tannages, but cannot 
permanently meet the wants of either American or English 
manufacturers. 

All sole leather should have the stretch taken out of it so 
completely that when the sole is cut by machinery there will 
be no waste, as it goes on the bottom. It should exactly fit, 
without any paring or loss. 

Leather may be too hard as well as too soft, but it cannot 
be too solid. Keeping in view the distinction between " hard" 
and " solid," the reader will understand that solid leather is 
a well-packed fiber, which cuts " cheesy" and " smooth," and 
not dry and " husky," as much of the vitriol raised leather 
cuts, increasing in these undesirable qualities with age. 

The leather is rolled for the first time in the moist (" sam- 
mied ") condition previously described. The grain is fairly 
flattened and made smooth; the whole fiber is firmly packed; 
but there remain roller marks on the grain, and defects which 
must be overcome. How shall this be done ? Some will say 
— let the leather be fully dried and then brought back and 
rolled on the flesh side, grain side to the roller bed, and this 
will remove all marks on the grain from the first rolling, and 
will, besides, leave a gloss and finish on the grain which is 
most desirable. Much can be said in favor of this style of 
finish, and, perhaps, no one has been more influential in in- 
troducing it than the writer. But for all that, it is not the 
most artistic or desirable. It will do on hemlock leather, 
where mere color in the buff is sought, but where both 
"color" and a "velvety" buff is desirable, i. e., where the 
bottom, after being buffed, is to present a " soft nap," and at 
the same time a lively and beautiful flesh color, then some 
other process rnust bo adopted. This other and better pro- 
cess is a second rolling, immediately or very soon after the 



100 THE LEATHER MANUFACTURE. 

first. The sides, after the first rolling, may be spread about 
the loft, and within an hour after the first rolling the second 
rolling should take place from the flesh side, as the first was 
from the grain. It may even be of service to slightly re- 
dampen the grain in spots, if the leather is allowed to re- 
main as much as an hour in a dry atmosphere between the 
first and second rolling. 

The care required to finish " union crop " leather, as well 
as pure oak, is incomparably greater than is usually be- 
stowed on the ordinary hemlock, and yet the time is prob- 
ably not far distant when the same care will fully compen- 
sate the tanner in the latter as in the former tannage, par- 
ticularly where slaughter hides are used. Some of our union 
leather tanners are now turning their attention to pure hem- 
lock tannage, and their greater success in producing hemlock 
leather justifies the impression that more care in the finish 
of slaughter hemlock will well repay the tannner. One con- 
tinent has come to be well nigh convinced that hemlock bark 
is as serviceable in tanning as oak, and it is quite within the 
range of possibilities that another decade of years will bring 
the whole Eastern World to this conviction. 

The branch of the finishing business which may be called 
the bleaching process might profitably occupy a chapter by 
itself, but as the writer does not pretend to fully understand 
— and, if he did, would not commend the various devices of 
bleaching leather by sugar of lead and sulphuric acid, which 
is the most common practice in general use among fair lea- 
ther manufacturers — the suggestions on this subject will be 
compressed in this chapter. The practice now is to dip the 
sides alternately, first into a bath of sugar of lead, and then 
into one of sulphuric acid, until the coloring matter of the 
hemlock is fully removed. This bleaching process produces 
an immediate effect that is almost magical, but when the 



THE LEATHER MANUFACTURE. 101 

finished leather is exposed to the air and light for any con- 
siderable time the delicate pink and cream color turns to a 
" murky brown," and the finish is in all respects most objec- 
tionable. The only natural and honest bleaching process 
known to the writer is that of " sumac baths." After the 
hemlock sides have been cleansed of all extraneous matter, 
as before described, by the most effective mechanical device 
knowu, it must then be hung in a vat of warm sumac liquor, 
and plunged frequently for one day (and even a few hours 
will sensibly affect the color). Usually one bag of Virginia 
sumac will suffice for a pack of one hundred sides. This pro- 
cess will cost about five dollars for a pack, or five cents per 
side, weighing fifteeen to twenty pounds. The sumac liquor 
forms a vegetable acid, which acts most kindly on the grain 
of hemlock slaughter leather, not only removing (neutraliz- 
ing) the color, but softening the grain, and contributes very 
much to the whiteness and clearness of the buff. Hemlock 
leather thus bleached will retain its improved color for a long 
time, and never go back to that muddy and objectionable 
color so common where other bleaching processes are em- 
ployed. As it is the acid that effects the object sought, the 
sumac liquor should be retained long after its tannin has de- 
parted. As a mere tannin agent it is only valuable, as all 
goat and sheep skin tanners comprehend, while it is fresh, 
before the acid forms ; but for the purpose of bleaching hem- • 
lock leather, it is questionable whether the old cast off sumac 
of the morocco dresser is not quite as valuable as new sumac. 
At all events, some experiments that have been tried go to 
this extent in their conclusions. 

Slaughter hemlock leather, tanned with liquors of moder- 
ate strength, say 10 to 20 degrees, from the press leach, will 
come out with a color that is between the lemon and the 
orange; if to this we add tin • warm sumac process, we get 



102 THE LEATHER MANUFACTURE. 

a color so nearly a light lemon or a flesh color as to meet the 
requirements sought in the best oak leather. Indeed, for all 
fine work, whether men's or women's, the buff is superior to 
that of most pure oak tannages, for these have a " sickly 
white" which soils much more readily on the bottom than 
the flesh color of the hemlock or union tannages bleached as 
here indicated. 

This bleaching process is particularly serviceable on calf, 
and all grain finished leathers, including harness and bridle. 
No purely hemlock tannage will " take the blacking " so well 
as leather which has undergone this treatment. With it, hem- 
lock grain leather can be made to hold its color almost equal 
to that of pure oak tannage. Calfskins properly tanned in 
hemlock can, by this bath of warm sumac liquor, be made 
equal in color to the best French, German or Swiss ; indeed, 
the resemblance is much greater than that of skins tanned by 
pure oak tannage, for the French color is controlled by the 
" larch " bark, the equivalent of our " spruce," which, as all 
know, is a modified hemlock in color. Above all these con- 
siderations actual experiments seem to indicate that this su- 
mac process will add enough to the weight to pay for its cost. 
However this may be, it will add greatly to the intrinsic qual- 
ities of all upper stock and much to the beauty of the buff in 
sole leather. 

As directly connected with this subject, it may be men- 
tioned that for many years the union crop leather tanners 
used " sour milk " to wash the grain between the first and 
second rolling. This treatment not only "lightened up " the 
whole complexion, but removed clouded spots and even 
stains, and was withal a most harmless bleaching process^ as 
the light and air did not affect unfavorably the buff, any 
more than in any of the vegetable processes. But mineral 
acids are objectionable and should be avoided. 



CHAPTER XI. 

THE CAUSES WHICH AFFECT COLOE AND ASSIST IN 
THE MAKING OF A VALUABLE EMBOSSING GRAIN. 

WHY LEATHER SHOULD BE THOROUGHLY DRIED STRUCTURE OF THE GRAIN 

IMPORTANCE OF A PERFECT FINISH CARE TO BE TAKEN TO AVOID 

STAINS AND DISCOLORATION " CUIR " COLOR THE NATURAL HEMLOCK 

COLOR " RUSSIA LEATHER " COLOR FRAUDS IN SELLING HEMLOCK 

FOR OAK LEATHER DURING THE WAR COLORLNG TO BE DONE IN THE 

HANDLERS EFFECT OF " STRIKING " THE GRAIN. 

In the preceding chapter it has been insisted upon that 
leather should be thoroughly dried before being taken down 
to roll. The importance of great care in this matter may 
not be appreciated without some further attention to the pe- 
culiar nature of the " grain " and an examination of the 
causes which affect its structure, including its color and its 
embossing qualities. Some tanners, defending their practice, 
say, " Why occupy so much time in thoroughly drying the 
fiber of the leather, and then immediately thereafter dampen- 
ing down again ?" At the expense of seeming over nice, the 
writer will explain the reasons for taking this course. 

The immediate outside grain of leather is a thin tissue, 
hardly thicker than thin paper. Next to this is an inner 
grain, several times thicker than the first, and very much 
more spongy in its nature. Together these two structures 
are usually called " the grain," and for the purposes of this 
discussion may be treated as one. 



104: THE LEATHER MANUFACTURE. 

Much of the value of sole, harness, trunk and other leathers 
depends upon the appearance and condition of this grain. 
Upon this outer surface the harness maker and saddler stamp 
their forms and make their ornaments ; the currier and fin- 
isher stamps or presses the grain with dies, making imitation 
hog, goat or seal skins out of ordinary neats leather. The 
boot and shoe manufacturer first buffs, then stamps and 
otherwise embellishes the bottom of his ladies' and gentle- 
men's fine work, on this grain, and the manufacturers of the 
fin 3r leather fabrics emboss this surface with the most artis- 
tic forms. To enable these impressions to be made with 
proper effect and remain lasting — retaining permanently both 
form and color — the grain must be "clear," "bright" and 
"perfect" as to color, and "mellow," "elastic" and yet 
" firm " in structure. 

This, then, is the nature of the surface or grain which is 
to be kept bright, and from which all coloring matter must 
have been wa lied and cleansed as far as possible by previous 
manipulation. If any device could be employed to pack the 
main fiber of the sole leather, and at the same time leave the 
grain perfectly smooth, it would be most desirable not to 
pack or compress this grain at all, but leave it soft and im- 
pressible for the artisan who conies after the tanner; but in- 
asmuch as the inner fiber cannot be compressed by any 
known means without also compressing the grain, the next 
best thing to do is to so manage as to leave this grain as soft, 
elastic and compressible, and also as free from coloring mat- 
ter as possible. 

It is found by experience that the coloring matter of the 

I '.irk, when in a soluble condition in the fiber, will spread, 

when compressed, almost as readily as ink on paper, and for 

reason, after washing and cleansing the grain, it is found 

desirable to fasten the coloring matter in the fiber by evap- 



THE LEATHER MANUFACTURE. 105 

orating all the water, which will leave the coloring matter in 
k a dry, insoluble and fixed condition. This condition must 
not be disturbed — certainly not to the extent of making it 
soluble, by any after process of wetting ; if that is done, the 
pressure of the roller will bring the coloring matter to the 
surface, and nullify all the advantages gained by the original 
washing and scrubbing, for the grain is almost as porous and 
as susceptible of receiving stain as blotting paper, and, when 
in a natural and proper condition, as impressible under 
heav} r , as wax is under light pressure. 

All that has or can be said of the proper treatment of 
leather to get rid of coloring matter, after it has been im- 
properly placed in the fiber, should be subordinated to the 
better method of not allowing the coloring matter ever to go 
in the leather at all, or certainly not to the damaging extent 
which would render the extreme methods of mineral bleach- 
ing necessary. It is possible to extract the tannin from even 
our hemlock bark without so overcharging it with coloring 
matter as to damage the burling qualities of the leather. It 
is not necessaiythat all our leather should be white, or cream 
color; any other color, if only natural and bright, is intrinsi- 
cally as handsome and appreciable. It is only because the 
red color of the hemlock is thought to be extraneous that it 
is regarded as objectionable. It is because this color is 
thought to indicate our inferior quality or workmanship that 
causes leather having it to be condemned. 

The writer saw, in one of the first boot and shoe manu- 
facturers' show windows in London, the best English bend 
bottoms stained red, or in very close imitation of our hem- 
lock. This was his trade mark, and had been for many 
years. There was no attempt at burring, such as we ap- 
preciate in this country, but the bottoms were made per- 
fectly smooth with the the " long stick." Now, this only proves 



106 THE LEATHER MANUFACTURE. 

that there is no standard color which, of itself, gives value. 
The bright hemlock color is now sought in pocket-books, 
satchels, ladies' belts, book- binders' leather — and, indeed, 
in all Ihose leathers which go to make up the "art work," 
of which leather is the foundation. The French word 
"cuir," for leather, is to-day the name of the prevailing 
fashionable color — and this color is absolutely fabricated 
from hemlock bark ; yet when it is found in sole leather it 
seems a badge of disfavor, to be got rid of by any means, 
however artificial and even damaging to the intrinsic qual- 
ity of the structure of the fiber. 

The fashionable "cuir" color can be most artistically 
made and preserved with pure hemlock tanning, if only too 
much heat is not used in extracting the strength of the bark. 
For fear that all may not understand what is the limit of 
heat permissible, it may be said that no tanner who desires 
to make the best color possible should use over 80 degrees of 
heat on his bark. Hemlock bark liquors, obtained with this 
limited heat, applied to pelts or hides properly prepared, en- 
tirely freed from all lime, will produce a color in almost exact 
imitation of the French " cuir " color, or, to put the expres- 
sion into English, the " hemlock tan color." 

The celebrated Russia leathers that enter so largely into 
tli" fine "Vienna leather goods" are originally of a light 
lemon color, produced by the willow bark with which they 
are tanned, and they are afterward changed by dyewoods and 
mordants into various colors ; the most p pular is that al- 
ready indicated — indeed, it is sometimes called a " Eussia 
leather color " by way of designation, and yet all Eussia lea- 
ther as seen in the arts is colored artificially. 

A curious train of circumstances developed the impolicy of 
"hiding our true colors" during the recent rebellion. The 
army officers imbibed the prejudice which generally prevails 



THE LEATHER MANUFACTURE. 107 

that oak tanned leather was far superior to hemlock, and 
„ ere influential in demanding this kind of tannage in all their 
army equipment work, such as shoes, belts, harness, etc. All 
of the earlier contracts specified that the leather should be 
made from " oak," and in some of the departments " white 
oak " tannage was called for. Soon the disparity between 
the price of hemlock and oak rough leather became so 
marked that the temptation to obtain in some way for hem- 
lock leather the higher prices paid for oak became too great 
to resist, and curriers found a way to bleach the hemlock 
even to a lighter color than the natural oak, but by a process 
which greatly damaged the intrinsic quality of the leather. 
One of the first discoveries made of this fraud was the find- 
ing of a large lot of bayonet scabbard sheaths that had so 
rusted the steel which they were made to cover and hold as 
to make both leather and contents perfectly worthless. The 
writer was c died on by the Government to determine the 
cause of this damage. The decision was that, by reason of 
the mineral salts used in bleachiog, the dampness in the at- 
mosphere collected an amount of moisture in the leather 
which caused the rust on the steel. Then how could this 
damage be prevented in the future ? was the practical ques- 
tion to be determined. My suggestion was, to strike from 
the requisitions the demand for " oak tanned leather," and 
thus remove all temptation to make artificial oak ; but this 
practical advice was not heeded, and, more or less, during the 
whole four years of our war, the Government paid for oak 
leather and got greatly damaged hemlock. This policy on 
the part of army officers cost the Government millions of dol- 
lars, and the regulations under which this mistake was com- 
mitted are still, to a considerable extent, in force. 

Ihe first and best thing to do then is not to overcharge the 
tannin with the coloring matter by the use of heat, and 



108 THE LEATHER MANUFACTURE. 

second, if it is so overcharged, to get rid of it by washing and 
scrubbing and the use of vegetable acid, such as a warm 
sumac bath, for instance. A single liquor overcharged with 
coloring matter in the earlier stages of tanning will often 
leave its effect so permanently on the pack as to defy all 
after correction. 

It is a mistake too often made by tanners to suppose that 
the coloring of the pack is effected by the last layers. Ordi- 
narily the color given in the handlers is carried through to 
the end. Start the color right, create the proper mordant in 
the handlers, and then strong and even highly colored liquors 
may be used without causing serious damage. The writer 
once saw a tanner attempt to make union crop leather with 
the usual quantity of oak bark, by putting his oak in at the 
wrong time; he thought he should "finish off" with oak, 
whereas he should have used his oak as a mordant in his 
handlers and early layaways ; the result was, as might have 
been expected — failure. There is good reason to think our 
English friends have made this mistake in using our hemlock 
extract. They have used the extract at too early a period, 
hoping to cover it up by their light coloring materials at the 
end — whereas, if they had colored their packs with terra and 
valonia, and put the hemlock extract in their last layers, they 
would have produced a different result. 

The English custom of allowing their packs to " sweat " in 
piles before " striking out the grain " is founded on a sensible 
idea, and the practice even now of " striking " the grain rath- 
er than rolling the whole substance, is based on the practical 
wants of the trade. By this process the pelt is held in its 
natural state. The thickness is maintained, the edges (backs) 
are rubbed up and made to appear full, and thus a market 
value secured which would be sacrificed if the leather were 
dampened and rolled as is our custom. 



THE LEATHER MANUFACTURE. 109 

Whether the manufacturers of Great Britain and Germany 
will ever become accustomed to our compressing process, and 
give us credit for plumpness which we seem not to have, is a 
question to be determined by future experience. If we 
change our rolling for a stamping process, and make our fiber 
hard, while at the same time we compress it, we certainly 
shall suit our German, Swiss and French customers, for this 
is the method followed by them in finishing sole leather. 



CHAPTER XII. 
CONSTRUCTION OF TANNERIES— THE TURRET DRYER. 

HOW THE ADMISSION OF LIGHT AND AIR IS CONTROLLED IN THE TURRET 

DRYER ITS CAPABILITIES FOR DRYING LEATHER IN QUICKER TIME, 

WITHOUT REGARD TO THE WEATHER— ITS CONSTRUCTION, AND HOW 

ITS CAPACITY SHOULD EE PROPORTIONED TO THAT OF THE YARD HOW 

AND WHEN HEAT SHOULD BE USED HOW TO PREVENT DISCOLORATION 

OF THE LEATHER — SAVING OF LABOR IN THE TURRET DRYER. 

About the year 1864, at Sparrowbush, N. Y., the first turret 
dryer was erected. It was a six-story structure, with most 
of the improvements found in the present dryer. There is 
nothing new in drying leather in a tall building. Many of the 
old tanneries, built as long ago as 1830, had three lofts over 
the whole size of the tannery ; the floors in the two upper 
lofts were latticed, and were therefore in this respect like the 
present turret form of dryer. Bat the principle claimed for 
this improved turret dryer is that, both as to air and heat, 
there is perfect control, whereas, with any drying loft hereto- 
fore in use, the damp air of the yard found its way up through 
the lofts, and in all cases there were opening windows from 
each loft, which were depended upon to admit the external 
air, so that substantially all the air obtained came in through 
these upper openings. The effect was that the leather hang- 



THE LEATHER MANUFACTURE. 



Ill 



uig near the openings dried rapidly, while those sides hanging 
in the center of the loft remained unaffected, so that, before 
they could be dried, they were required to be transferred ; 
often they were many times " shifted." This shifting process 
was particularly necessary in the winter time, when the large 
box stoves, burning wood, placed in different portions of the 
lower loft, or in the yard and beam house, caused the sides 
hanging near to dry rapidly and greatly to discolor, while at 
twenty feet distant the leather would be frozen solid. 

The difficulties and great delays in drying sole leather by 
any of the old methods were among the most annoying inci- 
dents of the tanners' life. All these are entirely removed by 
the turret dryer. There is now an absolute certainty as to 
the time when the leather will be dry, and this does not in 
any necessary degree depend on the state of the weather. 

Among the advantages of this new form of dryer are the 

following : 

1. Drying in one-third the time— thus saving insurance 

and interest. 

2. Drying without regard to the state of the weather— thus 
at all times keeping the rollers supplied. 

3. Drying much more uniform in color. 

4. Drying without shifting, or labor of any kind except to 
"hang up" and "take down." 

These are some of the economies of the turret system of 
drying, but they might be enlarged upon. The principle 
claimed, as already stated, is the absolute control of heat, 
light and air ; with these three elements under control, it 
will be admitted that all the advantages claimed must 

follow. 

The building may be any number of stories high ; some 
are but three or four, and others are seven and eight. Of 
co irse, to erect a building high enough to contain eight 



■Q2 THE LEATHEE MANUFACTURE. 

stories would require very heavy timbers, and from both ob- 
servation and experience the writer would recommend but 
five stories, each about seven feet in the clear between beams 
—just high enough for a man to pass with his hat on. This 
structure need not be made of very heavy timber, and conse- 
quently would be inexpensive as compared with those build- 
ings that run up so high. The question of convenience of 
elevating the leather, whether in the higher or lower turret, 
need not be taken into the account, as this is done by ma- 
chinery. The building should be about two spans of timber 
wide— say forty feet— with two rows of posts, equidistant 
from the sides. Longitudinally with the two rows of posts 
should run a tight board partition, with intersections at every 
ten feet extending to the sides. This would cut the space up 
into two rows of rooms of about 10 by 12 feet each, with a cen- 
ter passage of about 13 feet. The roof is made in the usual 
latticed lantern form. 

All the floors above the first or ground floor should be lat- 
ticed, and the rooms would, of course, be immediately above 
each other, so that, if the building were five stories high, 
there would be five rooms 10 by 12 feet each, standing one 
above the other, and there should, of course, be just as many 
of these rooms, or series of rooms, as would be required to 
dry the stock of the yard, whatever its capacity might be. 

Each one of these rooms will contain one pack of a hundred 
or one hundred and twenty sides, depending upon the weight 
of leather, and will dry the same in ten days. This would 
give the series of five rooms the capacity of drying fifty packs 
in ten days, or about fifty sides of heavy sole leather each 
day. Just so many times as fifty will go into the entire daily 
production of the yard will the tanner require duplicates of 
this series of rooms. 

The rooms on the first floor should be supplied with steam 



THE LEATHER MANUFACTURE. 113 

pipe, laid on the floor, or raised a few inches only by strips 
of hard wood, covered with hoop iron. The piping furnishing 
heat for each of these rooms should be under separate con- 
trol, so that not only could the steam be turned on or off from 
each, but any degree of heat might be admitted. 

All the packs taken out in one day, or in two or more days 
in succession, should go in one of these sections, so that the 
condition of the leather may be as nearly uniform as possible 
in each set of rooms. The leather is hung up on sticks in 
double rows, leaving a passage of nearly two feet between. 
For the first three or four days no steam should be allowed 
in the pipes or the section, nor should the trap doors which 
lead outwardly be opened but slightly if the weather is warm 
or the winds blow high, but in the fall, or when the weather 
is overcast, the lower trap doors may be safely left open. 
About the third or fourth day a very low degree of steam 
heat may be allowed in the pipes, and this may be gradually 
increased until the seventh to the tenth day, when it may 
certainly be premised that the leather will be fully dried; 
then all the sides in both tiers, and in all of the five rooms, 
will be dried about the same time, and may all be taken out 
and replaced by other sides. The writer has known turrets 
to be so actively worked as to turn out stock in seven days, 
but ten days' time is not too much, since it is very important 
not to hurry the drying the first few days. 

It has not been stated that the center passageways should 
be lighted by cross sections leading to the windows, nor that 
each room should contain one small window close to the top, 
(but to admit light only), nor that there should be no open- 
ings except at the base of the lower room, with the air lead- 
ing directly on the piping — all these are questions of detail 
that will be studied by any tanner who attempts to replace 
Lis old method by this new and better one — i ir often the gen- 



U4 THE LEATHEE MANTJFACTUKE. 

eral plan here outlined must be modified to meet the new 

conditions. 

The "turret dryer" is beyond all question the most 
thorough and efficient method yet devised for drying lea- 
ther, and in some of its modified forms should be adopted 
by aH tanners. The difference in the temperature of the 
atmosphere at the ground and at an altitude of 40 or 50 feet 
would, of itself, create a draft, as is well illustrated by the 
erection of "stacks" or "chimneys" for the passing off of 
smoke or gas. But if to the natural action caused by the 
difference in the temperature we add a little steam heat, a 
steady, yet moderate circulation will be maintained from the 
bottom toward the top or openings of this structure, carrying 
upward and off the dampness of the leather, without creat- 
ing such violent currents of air as to injure the color. 

It is believed that the principle which underlies this meth- 
od of drying sole leather could be applied with equal advant- 
age to all other kinds of leather— calf, upper, harness, sheep, 
goat, and particularly such of these as are to be finished 
"fair," without injury to the color of the grain. 

Keturning to the construction of these turrets, it may be 
remarked that the center passageways will be found useful in 
affording room to run the trucks with green leather, or to 
store the dry leather awaiting the roller. Some tanners pre- 
fer to have shutes running through each loft, down which 
they slide the leather as soon as dry, to be piled on the low- 
er floor. Others make their lattice floors of a temporary or 
movable structure, so that the whole contents of each room 
is dropped down into the lower room, including all the sticks 
, »ii which the leather has been hanging. The writer does not 
thiiik this a good plan, on the whole, since the extra labor of 
separating the leather from the mass of sticks, and carrying 
them back to their proper place, is about as much trouble as it 



THE LEATHEE MANUFACTURE. 115 

would be to take the sides down in the rooms, and, with the 
aid of a suitable barrow or truck, run them to the slide which 
takes them to the dampening or storage room direct. 

There is a most economical elevator or lift which should 
be known to all tanners who propose to adopt this turret dry- 
er. It consists of an endless chain running from the extreme 
bottom to the top floor, ending under the roof. This chain 
should run in a wooden box, inclosed on three sides. The 
outward or open side will serve to attach the sides by means 
of hooks fixed to the links of the chain, say at distances of 
about four feet, depending on the rapidity with which the 
chain moves. The distances between the attaching hooks 
should be sufficient to enable the attendants to attach below 
and take off above the sides. By this economical method 
leather may be elevated to the highest loft with no more 
actual expense than if dried on the ground floor, and the 
sides, when once hung, remain until fully dried — thus saving 
all expense of " shifting," etc. 

"What has been said in another place upon the influence of 
light and heat upon color will measurably apply to this pro- 
cess. Leather dried in the open air will certainly dry dark, 
even if tanned with pure oak, and, if tanned with hemlock 
or a mixed bark, will darken to a damaging extent. If cur- 
rents of air reach the leather while in a wet state, a like 
result is produced, with the addition of great harshness of 
grain. If a bright light, particularly if the sun's rays reach 
the grain or flesh, the leather turns brown, and is perma- 
nently discolored. The influence of the direct sun's rays, or 
even the strong light of the sun on vegetation, is a good 
illustration of such influences on the color of leather con- 
taining vegetable acid in solution. The ordinary table celery 
is covered with earth as fast as it comes to the surface, to 
keep the light from it, so that it may be lohite and tendi r. 



116 THE LEATHER MANOTACTCBE. 

Pie plant which grows under a barrel or in tbe shade will be . 
white and not green. Grass that grows under eover, excluded 
from the light, is white, not green. This law of light applies 
to all vegetation. Availing ourselves of this principle, here- 
fore, we say leather that is intended to be fair in color should 
be dried in the dart, and as free as possible from currents of 

air. 

An illustration of the " turret" dryer, with further explana- 
tions of its construction and mode of operation, will be found 
in later pages. 






3* 



CHAPTER XIII. 

CONSTRUCTION OF TANNERIES — PLANS, FOUNDA- 
TIONS, ETC. 

THOROUGH EXAMINATION OF PRESENT STRUCTURES AND APPLIANCES AD- 
VISABLE BEFORE BUILDING — IMPORTANT CHANGES FROM THE PRESENT 
GENERAL USE OF STEAM INSTEAD OF WATER POWER — LOCATING ON 

"MANUFACTURING" AND "CULINARY" STREAMS A LOAM, CLAY, OR 

SANDY FOUNDATION FILLING IN BETWEEN VATS AND LEACHES WITH 

LOAM OR CLAY-— PLACING THE VATS THE " BUFFALO" VAT "BOX" 

VATS THE PROCESS OF " PUDDLING " IN SETTING THE VATS — UPPER 

CONDUCTORS SIDE AND END WALLS. 

As preliminary to all efforts to erect a tannery, drawings 
and working plans should be fully prepared. These plans 
should not be merely in the mind of the owner or builder, but 
they should be elaborately placed on paper, so that thcj- can 
be well denned and susceptible of examination and discussion. 
The writer has seen so many expensive failures by reason of 
neglect in this respect, that, at the risk of being considered 
superserviceable, he would insist that, first of all, when the 
erection of a tannery is decided upon (and before the plans 
are drawn), extensive visitations should be made to the best 
constructed tanneries^ where can be seen in practical use all 
the best-known improvements. The characteristic readiness, 
and even pleasure, with which American tanners show their 
works, and honestly discuss the merits of their methods, 
loaves no excuse for any man who proposes to erect a new 



118 THE LEATHER MANUFACTURE. 

yard not to avail himself of all the experience which has been 
obtained by others. On this trip of observation both the 
draftsman and the head mechanic should be of the company, 
and they should not stop short of visiting every tannery where 
a new idea can be obtained. 

Leaving out of view at present the question of location for 
the economical supply of bark, hides and other material, we 
will treat at present only of the proper location of the build- 
ings, irrespective of the markets for hides and leather, aud 
the bark supply. 

Until within the last ten or fifteen years, most of our tan- 
neries were driven by water power, and this fact caused the 
buildings to be erected not only on the immediate bank, but 
usually the foundations were placed on the bed of a stream. 
This close proximity to the water was made necessary to eu- 
al »le advantage to be taken of the " head and fall," thus se- 
curing the greatest amount of power to drive the machinery. 
Such locations have always subjected the tanner to great 
danger from the overflowing stream, and as these risks were 
not insurable, many men have been entirely ruined by disas- 
trous floods. But beyond these extraordinary risks, such 
locations were usually very expensive to prepare, since rocks 
and boulders had to be blasted and removed, and when this 
was done the foundations were often uneven and hard to ad- 
just to the conductors and vats which rested upon them. 
Since the substitution of steam for water power, all these 
difficulties, and many more which might be enumerated, are 
avoided. 

The tannery buildings should be located near a capacious 
and never-failing stream of water. The stream need not be 
large, for any direct purpose of the tannery, but a clear dis- 
tinction should be drawn between "manufacturing" and 
" culinary" streams, as the health laws and public policy of 



TIIE LEATHER MANUFACTURE. 139 

all civilized nations make a wide difference between these 
classes of water courses. If a tanner locates himself on a 
" culinary " stream, he is always liable to the complaints of 
his neighbors below him — and even on a manufacturing 
stream he should, as f ir as possible, avoid throwing his waste 
in the water way, for, according to opinions of some of our 
courts, he is responsible for all actual damage done even on 
such streams. But if a tannery is properly located and con- 
structed, it will be found profitable to retain and utilize all 
refuse animal and even vegetable matter, which so defile the 
stream when thrown in, and it really seems to the writer a 
providential and happy influence which intervenes to prevent 
the tanner from thus injuring himself. 

The location of the tannery should, if practicable, be on a 
loamy, clay, or at worst a sandy foundation. If possible a 
loamy foundation should be secured. Whoever doubts that 
loam is equal to or even better, practical^, than clay, should 
try some experiments similar to several which have come 
within my observation. Clay, if thoroughly worked, and 
"rammed" with great care, will, beyond all doubt, act as a 
good preservative of wood; but, by reason of the great 
amount of labor and care required in its manipulation, it 
often happens that the material is unequally worked, and 
spots of dry or unworked clay will be thrown in ; this per- 
mits the access of air, causing defective parts in the wood, 
and soon the soundness of the whole structure is destroyed. 
Loam is much easier worked, and defects in its manipulation 
can hardly escape detection. The experiment which is com- 
mended to all doubters is as follows : Take a common pail 
and fill with loam, mixing and mingling water therewith, 
until the whole mass is of about the consistency of very thin 
mortar ; then allow the contents to settle for a day or two, and 
the result will be that the water will stand on tou and the 



120 THE LEATHER MANUFACTURE, 

earthy or loamy substance will fall to the bottom, in such 
order and compactness as absolutely to form a sandstone ; 
indeed, it is just this process in nature that forms the sand- 
stone which we everywhere see. "When this loamy or earthy 
substance has fairly settled, holes may be bored in the bottom 
of the pail and the water v T ill not percolate through, but will 
remain on top and finally evaporate. 

The principle upon which this stone formation takes place 
mast be observed in filling in between vats or leaches, other- 
wise there will be failure. When the whole mass is in a 
liquid or soluble condition, and is at rest, the settlement 
1) gins, according to the law of gravitation, the denser or 
heavier particles dropping first, and then the next heaviest, 
and so on until the whole bod} 7 has settled just in the order 
of the specific gravity of its parts. 

Now, it must be evident that, if the best result would be 
secured when puddling in between the vats or leaches, the 
whole mass should go in together and be plunged and mixed 
so that this order of settlement and adjustment may be the 
result. When loam is thus placed in between the vats it is 
almost impossible that there should be any leak. The writer 
lias seen whole yards sunk without corking any of the joints, 
and yet all the vats remained tight. 

When from any cause the foundation is defective — when 
gravel or projecting rocks are likely to allow water courses 
to be formed — the interstices must not onlv be filled, but 
made absolutely tight, and even new foundations must be 
artificially formed with loam, to the depth of one foot at 
l<ast below the log conductors. If by any chance a water 
course should be formed under the yard, the entire profits of 
the tanner may run away. The tanner should remember 
that for a mistake in omitting to lay his foundations both 
deep and water tight, he is liable ever after to unconsciously 



THE LEATHER MANUFACTURE. 121 

"waste liis liquors. When it is considered that they are al- 
most as valuable as malt liquors, he will comprehend the im- 
portance of the greatest possible care. No brewer would 
hazard the possibility of a leak in his underground tanks, 
however small, nor should a tanner. 

When the foundation ground is thoroughly prepared — 
then, and not before, should the log conductors be placed. 
The vats may rest firmly on the conductors. The point of 
contact should of course be at the ends, where the tube con- 
nections are to be made. But in addition to the rest on 
this log conductor, timbers at least 6 bv 8 inches should be 
thoroughly imbedded in the loam formation, not more than 
two feet apart, thus supporting the vats uniformly and equal- 
izing the strain. Otherwise the vats will certainly leak after 
a short time. 

When the conductors and supporting timbers are placed 
evenly over the whole yard surface, there should be a renewed 
attempt to puddle with a thin loam mixture — so thin that 
the smallest aperture or crevice underneath will be filled 
effectually. 

At this stage of the construction there come in at least two 
different kinds of vat builders, with their plans of construc- 
tion, both having merit. The first plan is known as the 
" Buffalo " method. This designation comes only from the 
fact that the Buffalo tanners first adopted it. It contemplates 
the foundations prepared as heretofore indicated ; upon these 
foundations, plank, which with this plan should be at least 
three inches thick, are closely jointed and laid over the whole 
surface, and then spiked to the timbers. Sometimes these 
plank are tongued and grooved, sometimes only jointed up 
close, and when the plank are half seasoned the joints may 
be trusted to close by the action of the dampness swelling 
them tight; but a corking joint, well filled with oakum, is, in 



122 THE LEATHER MANUFACTURE. 

my judgment, much the safest reliance. After the flooring 
plank have thus all been evenly and permanently laid and 
corked, the grooving plane cuts the grooves, into which the 
planks of the vats are inserted endwise, so that, when the vat 
is formed by these prepared plank standing endwise, resting 
in these close-fitting grooves, each side and end of the vat is 
keyed up by a " wedge plank." 

The only advantage that this form of vat has over what is 
termed the "box" form is that there is no space wasted be- 
tween the vats, and, of course, if leaks occur, they can only 
be from one vat to another. In locations like our large towns 
and cities, where land is very valuable, this method of con- 
structing vats has generally prevailed, as it saves at least 
four inches space between them. The writer cannot, how- 
ever, but think that, both on the ground of economy of con- 
struction as well as safety, the box form is to be preferred. 

The ordinary "battened" and "box" vat is, in my judg- 
ment, the best, because the safer form, where lumber is cheap 
and where space is of no value, as is generally the case in 
new territory, where our tanneries are usually constructed. 
This form of making the vats may be thus described. After 
the preparation of the foundations, as heretofore indicated, 
boxes made of plank, either two or three inches thick, bat- 
tened together, are placed side by side and end to end over 
the whole surface. The battens are " dropped in" and "pass 
each other;" or, to use the mechanical term, "joints are 
broken," so that the battens form supports to both sides and 
ends of the vats that come into contact and adjoin each 
other. When thus placed, connections are made, by tubes 
through the bottoms, with the log conductors beneath, and 
the seams are thoroughly corked with "spun" oakum. The 
best form of making these seams, and the most reliable and 
economical method of making tube connections, it is impos- 



THE LEATHER MANUFACTURE. 123 

sible in words to communicate, but it may be assumed that 
whoever really intends to avail himself of these suggestions 
will think it worth while to investigate more fully before he 
attempts to put in practice ideas which, at best, are very 
imperfectly described in these chapters. There are economic 
methods of preparing the plank for these vats, which have 
been employed within a few years, which put to shame the 
older hand methods. Whether the plank for vats should be 
made of pine or hemlock timber, and whether from plank 
two or more inches in thickness, are matters of detail, which 
it would be foreign to the object of this chapter to consider. 
After these box vats have been placed, corked, and the 
proper tube connections made, then comes the important 
work of puddling. Many yards have been ruined for want 
of care in this particular. The vats must be filled with water 
just as fast as, and no faster than, they are "puddled in" 
from the sides and ends. Some tanners think it sufficient to 
hold the vats in place by putting weights on the top, or by 
studding from the floor upward, but neither of these forms 
should be relied upon, since the pressure of the concrete, or 
puddling, from below, is very great, and it should be met by 
an equal, uniform, downward pressure — such as only the 
weight of the water filling can give. The loam which is 
used to fill in between the vats should be placed convenient 
to the yard, should be prepared in tight mortar boxes before 
it is run in, and so thoroughly mixed that it will run in box 
shutes to any desired spot. Carrying in pails, or otherwise 
handling, makes slow work, and too often induces the throw- 
ing in of the dry loam and the attempt to mix by plunging. 
This form leads to air holes and imperfect puddling. The 
whole process should be carried through on a uniform sys- 
tem, and no slighting or imperfect work should be permitted. 
Mr. James Clewer, who was the author of this system, 



124 THE LEATHER MANUFACTURE. 

always claimed that it was possible to so perfectly puddle 
vats with loam as to render corking unnecessary. Indeed, 
he did establish two or three yards on this plan without any 
corking whatever, and to this day (now more than thirty 
years afterward) the yards do not leak outwardly, though 
some of the seams leak inwardly — that is, the drip and drain- 
ing of the loam finds its way through the seams, and dis- 
colors slightly, but only occasionally, the sides that come in 
contact with it. 

By omitting the precaution of filling the vats with water 
before puddling, the result will be not only that the vats will 
be raised from their foundations, thereby disturbing the 
tube connections, but the sides and ends will be forced in- 
wardly, so that ever after the shape of the vats will be dis- 
torted and their capacity lessened. 

The " caps " or alley flooring resting on the tops of the 
vats should be often raised to see that the filling has not 
given way. If, as is quite likely for the first few months, 
such giving way or sinking is noticed, great care should be 
observed in refilling. When once the loam has thoroughly 
settled and become fixed in place, it may be considered cer- 
tain that a perfectly tight yard is guaranteed for all time. 

Some tanners have an upper system of conductors through 
which they supply their vats with new and strong liquors. 
These, when new and perfect, are very convenient, but such 
conductors are not to be trusted. After a few years they be- 
come decayed and leak, to the great damage and waste of the 
liquor. No care in the placing seems adequate to keep the 
air from these wooden structures when made so near the sur- 
face, and when the air does reach the wood it is certain to 
rot it in four or five years. It is for this reason the use of 
these upper conductors between the vats cannot be recom- 
mended, even where they are partially covered with earth. 



THE LEATHER MANUFACTURE. 125 

It is far better to have the upper conductors wholly above 
the top of the yard, either in open shutes or in tight log con- 
ductors, where any leak can be detected. 

When a tannery is located on an earth foundation, the side 
and end walls need not be extended to the lower foundations. 
Excavations can be made, the yard placed and filled in, and 
side and end walls may be commenced on timbers laid within 
two or three feet of the surface. If the timber is laid below 
the frost, and below the point reached by the air, it will last 
forever, and it will be safe to lay a brick, stone or concrete 
wall from this timber foundation upward, say two or three 
feet above the surface of the ground, on which the sills of the 
building may finally rest, beyond the reach of the damp 
earth beneath. If the filling in on the outside of the vats 
has been thoroughly done, this filling gives a more secure 
foundation than the natural earth, and will save much ex- 
pense in the foundations. 

If it is thought desirable, as it is in the opinion of most 
tanners, to erect the frame before setting the vats, the frame 
can be supported by temporary posts, running down to the 
foundation, and the making of a more permanent foundation 
may safely be left till the filling in is done, as here indicated. 
It will be useful for all tanners to remember that hemlock 
is just as lasting under ground as pine or other wood. 



CHAPTEE XIV. 
CONSTRUCTION OF TANNERIES— LEACHES. 

ROUND OB SQUARE LEACHES THE DURATION OF LEACHES ABOVE AND SUNK 

IN THE GROUND HOW TO BUILD A ROUND LEACH HOW TO MAKE 

AND SET LEACHES IN THE GROUND THE CAPACITY OF THE SETS OF 

LEACHES TO BE PROPORTIONED TO THE SIZE OF THE TANNERY. 

The form and construction of leaches is a problem of 
great importance to tanners. Shall they be round or square ? 
Shall they be above or underground ? Shall they be con- 
structed of wood, stone, or brick, and, if the former, then 
shall oak, hemlock or pine be used ? How can they be most 
economically constructed ? How long will they last made of 
either of the materials or forms named ? All these questions, 
and others besides, will occur to the practical tanner who 
contemplates building a tannery ; they are included in the 
general question, What kind of leaches are the most econom- 
ical for tanners' use ? 

Since the introduction of the " sprinkler leach " most tan- 
ners have made their leaches round. It is quite a mistake to 
suppose that the patented improvement covers the use of any 
kind of a round leach. It is true, probably, that a round 
leach is better adapted to the " sprinkler " than any other 
form, and for this reason the patentees have adopted it. 
There certainly is nothing novel in this form since, on the 



THE LEATHER MANUFACTURE. 127 

Continent of Europe, all tanners use round vats, and leaches, 
too, whenever they use leaches at all. If, therefore, tanners 
conclude that round leaches are preferable to square ones, 
they are quite at liberty to use them without any patent 
claim. 

It is safe to assume that no leach made of wood, however 
constructed, will, if placed above ground, where air has 
access to it, last more than four or five years ; by that time 
leaks will become so plenty as to necessitate a renewal. It 
is said of a chain that the whole is no stronger than its 
weakest link ; so it may be said of a wooden tank or leach — 
the whole is no more lasting than its most imperfect stave or 
joint. Practically, then, whenever a single defect occurs the 
whole leach must be abandoned. It would never be wise to 
put new staves in a defective leach, anymore than the house- 
wife would think of mending an old water-pail by replacing 
a defective chime. 

In considering, then, the economy of round leaches placed 
above ground, we are to estimate the duration of one of these 
structures by its single parts, and not by its whole structure. 
The experience of the most successful tanner using these 
round leaches above ground will show that four, or at most 
five, years is the duration or life of one of these structures. 
Reference is here made to the tight round leach — a leach that 
can safely stand full of strong liquor without " receiving 
leaches" or "drips" standing underneath, for in this manner 
these leaches have always been constructed and worked. 
But if a tight plank flooring should be constructed, and the 
leaches placed above it, the writer never could understand 
why attention should be paid to a small leak; indeed, if the 
leach was never filled with liquor, why should there be any 
pressure on the joints? Why should there be any leak, or if 
there was, why should any loss or injury result? This as- 



128 THE LEATHER MANUFACTURE. 

sumes that the bark is percolated by the liquor as fast as the 
latter passes the sprinkler ; that the liquor never floods the 
bark — and, so far as the principle of the patented improve- 
ment is concerned, this form of operation would more fully 
answer the purposes of the patent than if a portion of the 
bark was flooded — that is, had standing liquor in the leach. 
Indeed, just to the extent that liquor stands in the leach the 
patented idea is lost sight of. It then becomes a press, 
rather than a percolating or sprinkler leach. The form of 
running these leaches should properly influence their con- 
struction, for there is no reason why a sprinkler leach, run 
upon the true principles of the patent, should ever rot or 
wear out, since, so long as the staves stand up or the bottom 
remains in, it will inclose and hold bark ; and, so long as the 
staves would hold together to guide and confine the liquor in 
its downward course, a sprinkler leach would still remain to 
perform its office. Of course this defective structure would 
necessitate a tight plank flooring beneath ; but, so far as the 
writer is informed, the patentee has never recommended this 
form of handling these leaches, and until he does we must 
treat them as tight leaches, and subject to be renewed once 
in four or five years, under the most favorable circumstances, 
when they stand above ground. 

In deciding upon the material to be used in building 
leaches, it should be understood that young, sound hem- 
lock is just as likely to last the allotted time as the best 
pine ; but care should be taken to have the staves made from 
uniformly young trees, perfectly sound and fresh — that is, 
just peeled and sawed, and not from either old timber or that 
which has been lying two or three years before being sawed. 
Young hemlock trees, say not more than one foot in diameter, 
sawed into staves six inches wide and two inches thick, can 
be manufactured, into tank or leach staves almost as fast as 



THE LEATHER MANUFACTURE. 129 

they can be picked up and passed twice through the hands 
of the employe. 

The writer gives a little detailed instruction upon this 
point, since, through unreflecting employes, he was once 
made to suffer many thousands of dollars' loss for the want 
of a proper knowledge of the economies of this subject. 
After the plank have been sawed of the requisite length and 
width — usually seven feet long and six inches wide — the 
staves in this rough form are beveled by a circular saw on 
both edges. This bevel, of course, is made to adjust to a 
circle of 8, 12 or 16 feet, depending upon the diameter of the 
leach. When the staves are thus uniformly beveled, they 
are laid in a circular form, ten or fifteen at a time, and are 
chimed out by a " chiming" or " grooving plane." After be- 
ing thus formed they can be set up around the round bot- 
tom into which they are driven, and where they are held to- 
gether by iron hoops, without calking ; such a leach will 
certainly be tight. 

The saw that makes the bevels should be about eight 
inches in diameter, and be very straight, fine and even in its 
set, so that a perfectly uniform surface may be secured. It is 
said ''uniform," rather than "smooth," because it has been 
often demonstrated that such a, surface, when pressed to- 
gether will form a tighter joint than can be secured by the 
hand plane, however much, pains may be taken to secure 
smoothness. Very great attention should be paid to the 
character of the material. Hemlock is so cheap and abund- 
ant that none need be taken that is not perfect, both as to 
soundness and uniformity of thickness. 

In making the bottom of the leach, hemlock plank, plump 
two inches thick, should be used if the leach is to be tight or 
twelve feet in diameter, and if it is to be sixteen feel in di- 
ameter then the plank should be three inches in thickness ; 

9 



]30 THE LEATHER MANUFACTURE. 

in both cases the edges should be chamfered down to a uni- 
form thickness of hvo inches " scant." On the supposition 
that the leach is to be made twelve feet in diameter, the 
plank may be sawed sixteen feet long, whsn they will cut into 
bottom plank to good advantage. But it is seldom worth 
while to attempt to economize so closely as to save the whole 
of hemlock timber, and therefore, at the expense of a little 
possible waste, only perfect plank should be used in the bot- 
tom. These, after being square-edsed with a small fine-set 
circular saw, should be laid down on a platform bench, and 
firmly griped together, secured by a temporary batten ; when 
thus placed a circle should be inscribed the size of the pro- 
posed leach. With a small whip saw this line should be very 
carefully followed, taking great care to make the cut square, 
and at a right angle with the surface of the plank. If this is 
done with care and with a suitably straight saw, there need 
be but little after-work with the plane to make the circle 
smooth and otherwise perfect. If care has also been taken 
to have the plank originally sawed of uniform thickness, a 
very little work with the plane will bring the edges to a uni- 
form thickness, so that when put together the outer rim of 
the bottom will exactly fill, and fit the chime groove in the 
stave, making a reasonably good, tight j int. 

We are now ready to sot up our leach, and we want round 
hoops of at least five-eighths or three-quarters irom. The 
lengths should, as far as possible, be purchased to suit the 
size of the leach. Usually this round iron comes twelve feet 
long, but it may be obtained of any length desired. There 
should be but one joint for each hoop — a sufficient length of 
iron being welded together to go completely round the leach 
—and the ends should come together in a cotterel, which 
may be of cast iron or hard wood. If one of the ends of 
the iron should have a screw cut on it for six inches, while 



THE LEATHEE MANUFACTURE. lol 

the other is firmly fastened in the cotterel, a nut and wrench 
will draw the hoop as tight as it could be driven, if the form 
of the leach was tapering in shape, as on a pail or ordinary 
wash tub ; but as it is desirable to have these leaches of uni- 
form diameter, this form of drawing together and holding the 
stave must be resorted to. 

There is nothing difficult or expensive in constructing this 
form of leach, if the proper skill and machinery are at hand, 
but without this machinery and this knowledge they are very 
expensive, and often fail of being tight. With the small saw 
and mandrel, which cost about thirty dollars, and a chiming 
plane, which will cost about eight dollars, these round leaches 
may be put together with ordinary carpenters' tools at a very 
inconsiderable cost. The cost of the labor need not be over 
ten dollars for an ordinary leach, twelve feet in diameter, and 
seven feet deep in the clear. The expense may be increased 
by a greater regard for permanency in its construction, as 
the material may be clear pine or oak, the hoops may be of 
heavier iron, and instead of four hoops (the usual number) 
there may be six. But in this, as in all tannery construction, 
as much simplicity and cheapness should be observed as is 
compatible with the service to be performed. The iron hoops 
used will last during the lifetime of several wooden struc- 
tures. On the whole there can be no doubt that round 
leaches, constructed as here suggested, should always be 
employed when the leaches are to be used above ground ; 
but for underground leaches, or leaches filled in with earth, 
quite a different construction is suggested. 

Until the introduction of the Allen & Warren sprinkler 
leach, square leaches set in the ground, in a packing of loam 
or clay, were in general use, and to-day are not abandoned 
even by our best tanners. A set of these lcadics, prop< 
placed and filled in, will last for twenty or thirty years ; in- 



-j^o THE LEATHER MANUFACTURE. 

deed with slight repairs to the top planks, they will last dnr* 
in- the lifetime of a tannery. The writer knows of several 
sets that are now in good order that have, with slight repairs, 
been in active use for more than a quarter of a century. 

The preparation of the ground on which these lenches 
stand should be made with even more thoroughness, if pos- 
sible, than that of the yard itself, since there is more weight 
resting on it, and more disturbance from the flow of currents 
of water. If the leaches are constructed with proper open- 
ings in the bottom, through which the spent tan is washed 
after the leaching process is over, then more than ordinary 
care should be observed in placing the under conductors, 
otherwise air will reach the plank flooring and cause it to 
decay. In all locations where a flow of water can be secured 
on the top of the leaches, provision should be made for this 
to wash out such portion of the spent tan as may not be 
wanted for the furnaces. Sometimes, however, the nature of 
the stream is such that tanners are not permitted to throw 
their refuse tan in the water way, and in such cases this 
economical arrangement cannot be availed of. 

Ordinarily these square sunken leaches are of 10 by 12, 12 
by 14, or, in exceptional cases, 16 by 20 feet, surface meas- 
urement, and usually about seven feet deep. If the leaches 
are of the smaller sizes, then planks two inches thick are 
quite sufficient; but if the larger size, then planks at least 
three inches thick should be used; not more, however, for 
the economical reason than from the fact that the press can 
be better controlled in the smaller sizes, does the writer 
commend this form of leach. Indeed, the number mid size 
of leaches should correspond to the size of the vats in the 
yard. The covering of one leach of bark should make one 
vat of liquor. There should certainly be no fractions. It 
should either be one, two, three or four vats of liquor. At- 



THE LEATHER MANUFACTURE. 133 

tention to this seeming detail will nmch simplify the manipu- 
lations afterward. 

The preparation of the plank for these leaches can be 
made by the same saw and mandrel which has been com- 
mended for the round leaches ; even the calking seam can 
be formed with this saw. No joint can be made with a hand 
plane that Avill hold oakum so firmly as with this saw joint, 
and the oakum joint is made much truer by the saw than it 
can be made with hand labor. 

When the ends, sides and bottoms have been battened 
properly, they are put together as in the case of the vats de- 
scribed in a previous article. Indeed, these leaches are but 
so many vats enlarged in size. 

In Great Britain the tanners make use very largely of 
brick and cement to form their vats and leaches. No doubt 
these materials make a very substantial structure, and as 
erected there, in cities and towns, and intended to last for 
all time, this construction may be the best. But some at- 
tempts made in this country to use this material have resulted 
in staining the leather. "Whether this difficulty could not be 
overcome with us, as the English tanners claim it is with 
them, it seems hardly worth while to consider, since timber 
is so much cheaper here than brick, particularly in the 
country, where all our tanneries are built. Wood plank will 
last fifty years, sunk in our usual way, and that is quite as 
long as our civilization will tolerate the existence of a tan- 
nery in one location. 



CHAPTER XV. 

CONSTRUCTION OF TANNERIES— FRAME WORK AND 
LOCATION OF BUILDINGS. 

WHY THEY SHOULD BE ONLY ONE-STORY HIGH FOR THE YARD AND BEAM 
HOUSE— SAVING IN INSURANCE BY SEPARATING THE BUILDINGS CON- 
VEYING LEATHER TO THE " TURRET " DRYER TRANSMITTING POWER 

TO DISTANT BUILDINGS PROPER SPEED FOR BARK MILLS AND ELEVA- 
TORS SIMPLE PROVISIONS AGAINST FIRE AND BREAKAGE, AND TO PRE- 
VENT DUST. 

A modern tannery is quite a different affair from one of the 
early Greene County (N. T.) structures. The various im- 
proved methods of heating and obtaining power have ren- 
dered it quite unnecessary to crowd into one building, as 
formerly, bark mills, rollers, hide mills, drying lofts, yard, 
beam house, sweat pit, etc. Heat and power can now be 
used without limit, and wherever their use can be made to 
economize labor or cheapen insurance they should be em- 
ployed. 

That great advantages are secured by a one-story structure 
over the yard and beam house will be conceded when the 
following points are considered : 

1. The timber need only be heavy enough to carry and 
uphold the roof, not forgetting, of course, its probable load 
of snow in winter. 

2. No apprehension need be felt about the falling in of the 
structure for a long time after the usual decay of the timbers 



THE LEATHER MANUFACTURE. 135 

commences, since they can be replaced without inconvenience, 
there being no heavy superstructure to sustain, whereas a 
building with lofts above, often filled with wet leather, is al- 
ways an object of solicitude to the tanner ; he is constantly 
studding up and "supporting" the building to make it safe 
for the workmen. Besides, these high structures are subject 
to the action of the wind, which much weakens their joints 
and fastenings. 

3. The insurance is only one half the price of what was 
paid on the old and high buildings. Although these one- 
story structures have now been in use for ten years or more, 
several hundred of them being in existence, not a single one 
has yet been destroyed by fire, and if this record shall not be 
changed by further experience, we may reasonably expect a 
still further reduction in the rate of insurance. In fact, with 
an abundant water supply and efficient service, a one-story 
tannery cannot be wholly destroyed, for nothing but the roof 
could burn, and as this can be reached from both above and 
below with ordinary water buckets, the progress of the flames 
can be stayed in almost any case of fire likely to happen. Be- 
sides, the condensation of water from the steam of the yard 
always keeps the roof boards and covering water soaked, so 
that fire would not spread rapidly, if at all. 

4. A building of one story for the yard gives opportunity 
for a high ceiling and good ventilation. It has, however, this 
single disadvantage — that in winter it is much more expos, <1 
to the frost, although, practically, ice seldom forms in a yar< I 
of this construction. Indeed, experience has shown that with 
a few coils of steam pipe running around above the sills there 
need be no cold fingers of the workmen. This one-ston- 
structure should have a flat roof (one foot pitch in ten) cov- 
ered first with . boards and then with asphalt paper and 
gravel, by a process universally in use. 



136 THE LEATHER MANTFACTURE. 

So far, then, as the yard and beam house are concerned, a 
one-story building is the most suitable structure. But how 
shall the tanned packs be got to the drying loft? Heretofore 
trap doors have been placed in each bent of the building, so 
that little more was needed than to open the trap and hook 
the sides from the yard below, and thus pass them up by 
hand from loft to loft, This seeming convenience prevented 
an}' change from the old method for many years. Tanners 
not unnaturally reasoned in this way : " We have a yard 
and beam house, and they must be covered with a roof ; the 
same roof can equally cover our drying lofts, aud as our dry- 
ing lofts must have a capacity as large as our whole beam 
house and yard, in order to dry our stock, why should we 
not make our structure strong enough to carry all this under 
one roof?" Besides, they have reasoned: "Our insurance 
covers our stock in both yard and loft, and at the same price ; 
why should we go to the expense of erecting a separate struc- 
ture, where our insurance would be divided, without any com- 
pensating advantages in the way of reduction of rates?" 
Thus reasoning, our tanners went on from year to year erect- 
ing new yards under former plans, until within the past ten 
years, during which many have been induced to break away 
from this old method, and are now building turret dryers in 
connection with the rolling or finishing lofts, connecting these 
with the yard by tramways, hung from above in some in- 
stances, and in others with bottom rails of wood, these tram- 
ways running cars through the center of the yard, extending 
out to the drying lofts. The form of erecting these tramways 
varies with each location. Where a tannery is situated on 
level ground, accessible on all sides by a horse and truck, 
probably there is not a more economical way of transferring 
the wet stock from the yard than by this, means. In this 
case the tanner can have openings from his yard at fre- 



THE LEATHER MANUFACTURE. 137 

quent intervals, and the nearness and saying of transporta- 
tion of the wet leather in the yard will compensate for the 
cost of the service of the horse and cart, over and above a 
tramway through the center of the yard, to which all tanned 
packs must be brought. 

The latest and most approved method of locating the 
buildings so entirely separates the yard from the drying lofts 
that the fire risks are greatly reduced, for the yard and beam 
house are one risk, the leaches and bark mill another, and 
the furnaces and boilers still another. The building contain- 
ing the latter should be placed at least 100 feet from all other 
structures, and in itself made perfectly fireproof — that is, 
there should be no wood anywhere near the structure con- 
taining the furnaces and boilers. So arranged, it is found 
practicable to run steam power off in any direction and al- 
most to any distance. The most economical way of running 
off this power is by means of steam pipe, thoroughly pro- 
tected with ashes, loam or clay, well packed in a box sur- 
rounding and inclosing the steam pipe. The engines that 
drive the machinery may be in distant buildings. Some tan- 
ners drive their machinery at a distance of from 300 to 1,000 
feet from the boilers, and the condensation does not seriously 
affect the power, a portion of which is necessarily lost, but 
when wet spent tan is burned this loss has no commercial 
value. 

It has been demonstrated that steam power can be con- 
veyed in pipes more economically than by running shafting ; 
that is, wherever power is required a steam engine should be 
placed and steam conveyed to it, rather than to depend on 
one central engine, and either " belt " or " shaft " off. Engines 
are now constructed so strong and cheap, and to run with so 
little attention, that one engineer can take care of two or three 
with the same facility as one. The steam valves are opened 



138 THE LEATHER MANUFACTURE. 

in the morning, and are not shut or otherwise disturbed until 
noon, and then again are opened at 1 p. M., and not closed until 
sundown. So different is this practice from the old method, 
and the care made necessary by the defective character of 
steam engines, as formerly constructed, that engines may 
now be multiplied to any required extent without making it 
necessary to employ an assistant engineer. 

It may be safely estimated that a one-story yard and beam 
house, isolated at least 100 feet, can be insured for 1J per 
cent., while 3 and even 4 per cent, is now charged on ordi- 
nary tanneries constructed after the old methods ; but no in- 
surance is needed on the leather in the vats, for neither the 
leather nor the vats themselves will burn, even if the frame- 
work above is destroyed. 

The turret drying loft (of which mention has been suffi- 
ciently made in a previous chapter) should be near the yard, 
and should be classed in the same risk ; but the leach house 
and bark mills should be in an opposite direction, and as far 
as possible from the central or boiler house and furnaces. 
Where the ground will permit, the boilers and furnaces 
should be in the center, the leach house and bark mills fully 
one hundred feet to one side, and the yard and turret drying 
lofts as great a distance in the opposite direction. This will 
bring the important structures two hundred feet apart, and 
if the boiler and furnace building is built as it should be, of 
stone or brick, and is not over fifteen or twenty feet high, 
there is really an unobstructed space of two hundred feet be- 
tween the main fire risks. There is really no manufacturing 
structure in the country so free from accidents by fire, when 
thus constructed and situated, as one of these one-story yards 
and beam houses ; and the drying lofts, always filled in part 
with wet or only partially dry leather, have a moist or damp 
atmosphere which, with steam pipe only used as heaters, 



THE LEATHER MANUFACTURE. 139 

renders anything like accident from fire almost impossible. 
The natural, and, indeed, the only fire risk about a tannery, 
comes from the bark mills and bark elevators, and in a vast 
majority of cases the fires which consume so many tanneries 
proceed fi om this source. How can this risk be lessened or 
altogether avoided? The bark mills and elevators should 
have a slow motion. No mill should run above sixty to 
eighty revolutions per minute, and the elevator belt should 
run slow enough to enable the eye to take in and count the 
buckets or boxes as they pass a given point. The sli overs 
and screen should move slowly, for besides the friction which 
causes fires there is much more wear and tear to a quick 
than to a slow motion, and power is also lost. 

An improvement has of late been suggested to suppress 
the dust arising from the fine ground bark, as follows : A 
steam pipe, half an inch in diameter, connected with the 
nearest direct pipe from the boiler, is brought to the under- 
side of the mill ; a very small jet of steam is allowed to es- 
cape, to dampen by condensation the bark as it comes from 
the lower throat of the mill, and before it drops into the- con- 
veyers. This steam pipe could be so placed that if fire 
should occur in the elevators, from friction or otherwise, a 
full head could be turned on by the attendant, and steam 
forced upward through the entire length of the elevator box. 
This, therefore, may be regarded as an inexpensive contriv- 
ance to prevent dust, and also as a great safeguard against 
fire; and now that steam fs so cheap and abundant there 
seems no reason why it should not be adopted by all t,i li- 
ners, especially as it is regarded by insurance companies 
with great favor. Bark elevators are liable to get choked 
and stop; when this occurs the bark accumulates and gets 
packed in the lower part of the mill; great friction and dan- 
ger from fire arises from this source, and to avoid the danger 



140 THE LEATHER MANUFACTURE. 

an "overflow" or space under the mill should be provided. 
But a " tell tale " should be put on the elevators, plainly in 
the; sight of the bark grinder, so that he can see when there 
is a stoppage. Some tanners think it a sufficient precaution 
to have an opening in the elevator for this observation ; but 
a " tell tale " should also be placed on the elevators, and this 
small and inexpensive lever should, in its rising and falling 
motion, indicate its action by a slight noise, so that if the 
eye is otherwise directed the ear of the attendant will notify 
him of the danger, which is from breakage as well as fire. 



OHAPTEE XVI 
THE ROSSING OF BARK. 

THEORIES OF THOSE WHO ADVOCATE ROSSING ITS COST DIFFICULTY OF 

ROSSING WITHOUT TOO GREAT LOSS OF TANNIN STRENGTH OF 

LIQUORS WHICH MAY BE OBTAINED FROM ROSSED AND UNROSSED 

BARK POSSIBLE ADVANTAGE IN ROSSING BARK FOR EXPORT IN THE 

"LEAF." 

To what extent, and under what circumstances, should bark 
be rossed before being ground for tanners' use ? If credit be 
given to the statements of parties interested in the manu- 
facture and sale of rossing machines, tanners will be led to 
the conclusion that rossing is an absolute economic necessity. 
As the writer does not agree with this sweeping conclusion, 
and yet believes that there are circumstances under which 
it is profitable to ross bark, the limitations which should 
govern in this matter will be briefly considered. 

The theory on which the rossing of bark is advocated may 
be thus stated : 

1. The outer ross, or dead bark of the tree, contains no 
tannin . By the exposure of its weather-beaten surface to the 
rains and winds, all but the woody > fibrous structure has 
been destroyed. To place this porous, spongy, woody fiber 
in contact, as when ground, together with the extractive and 
tannin matter of the live portions of the bark, which arc 
charged with tannin, is to absorb and dissipate this valuable 



142 THE LEATHER MANUFACTURE. 

product to no purpose. Iu fewer words, this woody fiber 
will thus be fanned, and this it is claimed is wasteful. 

2. The space which this ross occupies in the leach displaces 
so much good bark, and to this extent retards the leaching 
by lessening the capacity of the leaches. 

3. This dry ross is a valuable fuel, and can be used to some 
advantage in the generating of steam or for other purposes. 

Against these advantages should be placed the cost of ross- 
ing, which is quite inconsiderable, if the advocates of ross- 
ing are to be credited. Conceding all that is claimed for this 
practice, it is impossible by any machine yet invented, or even 
by hand labor, to separate the worthless ross from the live 
baric so exactly as to make the process profitable for ordinary 
tanners, who buy and use their bark at home in the interior 
locations. Let any tanner who doubts this statement exam- 
ine carefully the ross coming from any rossing machine. Let 
hi in place a limited quantity under the influence of hot water, 
and the tan liquor present will be a convincing proof of the 
inexpediency of the practice. Or let him take a piece of 
bark no more than one foot square, weigh it carefully, and 
then, by hand process, with the aid of a sharp knife, let him 
attempt to remove just the colorless dead ross, and no more, 
taking great care not to touch the live bark. After this is 
done contrast the percentage of rejected ross with the per- 
centage obtained by means of the rossing machines, and the 
result will show just how much live bark is taken for ross, to 
burn up, by the use of the machine. This latter experi- 
ment, conducted never so carefully, will also prove how im- 
possible it is to divide exactly and positively the dead and 
worthless, from the live and valuable bark. If it cannot be 
done }>y hand, even in a small experimental way, how much 
more impossible is it to do with a machine which cuts the 
thin and thick bark alike— notwithstanding all attempts to 



THE LEATHER MANUFACTURE. 1-43 

adjust the knives and rollers to suit the substance of the Lark. 
The testimony of tanners differs as to the percentage of 
ross removed; most of them, however, agree that even one- 
iil'th, or 20 per cent., is about the average loss. Some chemi- 
cal tests of the comparative strength of rossed and unrossed 
bark have been made, and, naturally enough, the percentage 
of tannin in the rossed bark has been found in excess of that 
in the unrossed. But a recent and a more satisfactory ex- 
periment gave the following results : A pi nee of average 
hemlock bark was weighed — we will suppose the weight to 
have been sixteen pounds. This piece was first cut evenly 
in two parts, and both parts were afterward made to weigh 
exactly alike. The ross was carefully removed from the one 
piece by a hand knife ; (only about one-tenth of the weight 
was removed, showing the care with which it was done.) 
Both pieces were then separately ground fine, and leached, 
great care being observed to continue the equal condition all 
through the experiment. The result was, by the barkometer 
test, the extract obtained from the unrossed portion stood 
higher, that is, indicated a greater degree of tannin, than 
that portion which had been rossed. This is an experiment 
which any tanner can try in a few hours, and at small cost 
of time and labor. If the experiment is tried accurately, it 
will be found that, without considering the cost of rossing, 
there is a positive economic loss in the process. In no in- 
stance, however, has the strength differed equal to the loss 
of the ross, which we assume to be 20 to 25 per cent. The 
experiments show that hemlock bark that is rossed will give 
8.66 per cent., while the same bark not rossed will give 7.1:5 
per cent. The experiment was made by a celebrated Boston 
chemist in the iuterest of the patentee of a bark rosser, and 
may at least be taken as the most favorable result which can 
be produced. 



141 THE LEATHER MANUFACTURE. 

If this is the result of the comparative strength of bark, 
rossed and unrossed, we are left to consider on the one hand 
the cost of rossing, and on the other the value of the dry 
material. The cost of rossing, independent of grinding, may 
fairly be placed at fifty cents per cord, and the dry ross ob- 
tained equal to 400 pounds. Is 400 pounds of ross worth 
fifty cents? Of course this would depend upon the value of 
fuel in the locality. To the ordinary tanner the dry ross is 
worthless, and wou'd hardly pay for its removal, since the 
wet spent tan furnishes far more steam power than suffices for 
driving the whole machinery of the tannery, and dry ross is a 
poor substitute for wood anywhere else than under a furnace. 

But there are circumstances which would justify rossing 
as, for instance, if bark had to be transported long distances, 
where the cost of transportation was a considerable item of 
the value ; or, if the bark had to be " baled,'; and the freight 
was based both upon bulk and weight, then would it be es- 
pecially necessary to ross. It has often occured to the writer 
that both the English and German tanners would find it prof- 
itable to buy our oak and hemlock bark and closely ross and 
bale for shipment to their market. Rossed bark in the " leaf" 
will occupy one-quarter less space than when "in the rough," 
and with care may be so compactly placed in a bale as to 
make solid stowage — so solid, indeed, that no ordinary lev- 
erage can compress it. When thus baled, and bound with 
wire, there can be no doubt that bark could be sent to Europe 
from many of our Southern ports to advantage. The cost 
would be as follows : 

Original cost of oak bark, per ton $10 00 

Cost of freight to seaboard 4 00 

Cost of baling and rossing 2 00 

Freight to Liverpool 5 00 

Total $21700 



THE LEATHER MANUFACTURE. 115 

Southern oak bark, thus rossed and baled, would give Eu- 
ropean tanners better and cheaper tanning material than 
they at .present employ from any barks in the "leaf" or 
"chip" which they now use. Whether " extract " from this 
bark could not more economically be sent abroad, is quite a 
different question, which the writer will 'not here enter upon. 



10 



CHAPTEE XVII. 
UTILIZATION OF TANNEBY EEFUSE. 

BURNING THE WET TAN GLUE STOCK IMPORTANCE OF KEEPING THE 

PIECES PURE AND SWEET PRESERVING, CLEANSING AND DRYING THEM 

USES FOR CATTLE HAIR THAT WHICH COMES FROM SWEAT OR LIMED 

STOCK — WASHING, DRYING AND PACKING FERTILIZING LIQUIDS FROM 

THE LIMES AND SOAKS. 

Previous to the year 1852 it was customary in all the tan- 
neries of New England to dry, or partially dry, in the open 
air, all the spent tan from the yard and leaches, and store 
during the summer months for winter use, not only for heat- 
ing the liquors, but, in exceptional cases, to generate steam 
to furnish the power for the ordinary work of the tannery. 
Even up to this day the practice is regarded as most eco- 
nomical by the upper leather tanners, and such others as do 
much finishing. None of the patented, or unpatented, meth- 
ods of burning wet tan can secure as good a result with wet 
as they can with dry tan. Experience has shown that from 
one-third to one-half the effective heat-producing power is 
neutralized in driving off the water. In other words, there 
is no method of burning wet tan that does not first evaporate 
the water. Therefore, when there is an inadequate supply 
of tan, and it is convenient to dry it, it is always better to do 
so. But in the ease of our sole leather tanners, they have a 



THE LEATHER MANUFACTURE. 147 

surplus of wet tan, and to waste it by burning a profuse 
quantity is to save the expense of otherwise disposing of it. 

In the year 1852 Mr. Joseph B. Hoyt conceived the idea 
of burning wet spent tan in a detached brick furnace, and 
did for the first time in America succeed in obtaining the 
power to drive his machinery by this agenc}^ unaided and 
alone. This was done at his tannery at Woodstock, Ulster 
County, N. T., and the event has been made memorable by 
the great success which has attended the practice ever since. 
This improvement revolutionized the construction of our tan- 
neries. It rendered water power of little or no value. It 
caused tanneries to be located upon open flats, where access 
could be had from all parts to the buildings, and took them 
from the banks of the streams, where floods and overflows 
did yearly great damage ; it rendered unnecessary the use of 
wood or coal for the heating of liquors, or the warming of the 
lofts, and, by the unlimited and inexpensive use of this newly- 
acquired agent, labor saving machinery was introduced every- 
where. 

The controversy about the priority of the invention or use 
of wet spent tan, commenced in 1869, occupied the attention 
of one of our courts for six years or more, and the decision 
finally reached was that Mr. Hoyt and his agent, Mr. Crock- 
ett, did introduce these wet tan burning ovens as earl}- as 
1852, and by their use a result was obtained equal to any 
which has been secured by an} r improvement since made. 

Notwithstanding the publicity which has been given to the 
construction of furnaces for the utilization of this refuse, 
there has been no one specific plan that has received general 
commendation. So many of these furnaces have been adapt- 
ed to the condition of the structures already in existence, 
that, with the exception of those tanneries built within the 
past ten years, there has been no consistent and harmonious 



148 THE LEATHER MANUFACTURE. 

plan of construction. With a fuel so abundant, and withal 
so worthless, economy in the consumption was best studied 
by practicing the most wasteful methods, and hence it has 
been customary for tanners to economize in the construction 
of their boilers at the expense of their fuel. "Log" or "cyl- 
inder " boilers being much cheaper and more durable, they 
have in many instances been introduced instead of "flue" or 
" tubular " boilers, not because they were more economical, 
but in truth because they were more wasteful of fuel. Sev- 
eral of our tanners have been compelled to construct brick 
furnaces outside and independent of their ordinary boilers, 
in order to " get rid of " their surplus spent tan. As time 
goes on, however, and as we come more generally into the 
use of mechanical power, there will be less solicitude to get 
rid of this refuse without bringing it within our service. No 
town or city is without its mechanical appliances, and if the 
power or heat is not required for the tannery, it can be ap- 
plied to some other purpose. It may be sent off to the dis- 
tance of several hundred and even several thousand feet to 
drive an elevator or an engine, or warm some dwelling or 
manufactory. There is no reason why all the power should 
not be utilized, and hence the writer would strongly commend 
the use of tubular or at least flue boilers in all cases. 

As the subject of burning wet spent tan, both in its eco- 
nomic and scientific relations to the tanner, is considered in 
a subs quent portion of this book, the subject may be dis- 
missed for the present with the statement, which seems nec- 
essary in this connection, that the spent tan can be so utilized 
as to give all the power required by the tanner in softening 
his dry hides, in grinding his bark, in rolling and finishing 
his leather, in warming his building, in heating his liquors, 
and in doing such other service as may be done by mechanic 
ical power. 



THE LEATHER MANUFACTURE. 1-10 

The glue staok, of which every tanner has more or less, is 
valuable almost in proportion to the care bestowed upon its 
preservation, and this is true without considering the higher 
grades of gelatine which are made from calves' pates and 
feet, and the sinews from neats animals. These are, or 
should be, preserved by the slaughterer, and handed over 
to the manufacturer of gelatines for human food. In the 
preservation of tanners' hide offal, as it is known to come 
from ordinary dry and green hides and skins, it is of the first 
importance that the '"glue" or "size" pieces should be 
sweet and pure from all "taint" or "smell." The paper 
makers use animal "size" very extensively, and such as they 
use must be absolutely free from all bad odors, otherwise 
the paper is rendered worthless. With all the care which 
the paper makers exercise they do occasionally use "tainted" 
size, and the odor will cling to the paper forever, greatly less- 
ening if not entirely destroying its value. Next in import- 
ance to paper size comes the fine glues which are used in 
book and furniture work. In these, too, it is of great im- 
portance that there should be perfect purity and freedom 
from all smell. It is only for the most common use, such as 
preparing petroleum barrels, sizing woodwork, etc., that glne 
that has been in the least tainted can be used ; therefore it 
is that the value of this stock depends almost entirely upon 
the care taken in its preservation from all bad odors. 

"When the hides or skins are either fresh from the animal 
or have been properly cured with salt there is no difficulty 
in avoiding all decomposition — indeed, nothing but absolute 
carelessness can bring harm to the "glue pieces." But it 
the pelts have been dried, and require to be softened before 
being limed or sweat, then it is that care and close and 
prompt attention should be given to the preservation of tins 
valuable offal. Whether from green or dry stock, the trim- 



150 THE LEATHEK MANUFACTURE. 

mings should be thrown into a weak lime as soon as they leave 
the beam, and should be retained in this lime until the hair 
will almost drop off; when in this condition they should be 
thrown into a revolving wheel, or may be put in the hide 
mill, and worked until all the hair has been separated from 
the pieces. If a bountiful supply of water has been allowed 
to run on while the wheel or mill was in operation, all the 
hair will have been worked off and separated from the 
pieces, which will then have parted with so much of their 
lime as to make them, when dry, flinty and hard ; to avoid 
this thej- should be thrown back into the lime for a few days, 
and again " raised." Before they are taken out to dry they 
should be thoroughly washed. The drying should be in the 
open air, and if on a flat board surface then the pieces should 
be frequently turned. Care should be taken to wash off all 
the loose lime, so that the pieces may present an attractive, 
uniform white clean surface. "When they are fully dried they 
should be prsssecl into uniform bales. Under no circum- 
stances should any tainted or damaged piece be allowed to 
go in the bale. Paper makers will use such hide offal for 
sizing, and pay three or four cents per pound more for it 
than glue makers can afford to pay. Calfskin shanks and 
pates are worth more for this purpose than hide cuttings, 
and should always be kept separate. 

Until within a few years cattle and calves' hair have only 
beer used for plastering purposes, and for this the harshness 
produced by the liming process rather added to than de- 
tracted from its value ; but more recently this hair, particu- 
larly the calves' hair, has been used for cloth, carpets and 
felting, and for these purposes it is required to be soft, which 
necessitates freedom from lime. Probably it will be ulti- 
mately demonstrated that the hair from hides that are un- 
haired by sweating, so far as the length (as in winter and 



THE LEATHER MANUFACTURE. 151 

spiing hides) will serve, is far superior to limed hair for this 
very reason. Millions of pounds of this valuable product, 
that should have at least gone on the "fertilizing heap," if 
its length had been too short for cloth or felting, have been 
washed down the streams. 

It is important to select the white hair from all other colors, 
a& it is worth nearly or quite double the price of the general 
stock. This selection is not attended with much inconven- 
ience if done while the beam work is in progress. If the hide 
or skin is white, or mainly so, it should be thrown to the beam 
hand whose duty it is to unhair this color ; when he has re- 
moved all the white hair he passes the skin or hide to his 
companion, and so in turn they pass to him all their pelts 
that have any considerable amount of white hair. In this 
way a single beam hand accumulates at his beam all the 
white hair, and of course it can be easily dried and kept 
separate. 

The cleansing of the hair from the lime is attended with 
little or no expense. Throughout Europe it is washed by 
hand, large splint baskets being used ; filling a basket about 
half full, an attendant, stdftiding on the bank of a stream, 
plunges it in and lifts it up until the currents of water passing 
through carry off most of the lime. But in this country a 
vat with a false bottom is used to better effect. The vat is 
placed so as to command a bountiful supply of water, and it 
has a false bottom bored fall of small holes — large enough to 
allow the lime water and small particles of lime to pass 
through, while retaining the hair. While the hair is covered 
with water, and is being plunged, the openings in the bottom 
must be closed ; when the agitation of the contents is com- 
pleted, the plugs may be drawn from the bottom, and, prac- 
tically, the particles of lime having gone down below the 
false bottom, the hair will mat together, settle down and rest 



152 THE LEATHER MANUFACTURE. 

on the false bottom ; very little or none of the serviceable 
1 >ng hair will have passed out. This process of Ming, plung- 
ing and draining off may be repeated a dozen times during 
A he day, and the hair will be fairly cleansed. If it is desira- 
b 3 to cleanse the fiber of the hair from the effects of the 
li ne, warm water run on the last time, and allowed to remain 
for a short period, will greatly aid this result. This latter 
process will leave the hair much softer than if cleansed only 
with cold water. When it shall be established, as now seems 
pr -.1 able, that all calves' and cattle hair can be utilized in 
in iking coarse blankets, cheap carpets and felting, other 
methods for neutralizing the lime will come into vogue. 

Never until within the past few years has the hair from 
hides unhaired by sweating been saved. Whether the hair 
was long or short it has all been allowed to pass down the 
stream from the mills, or if saved from the beam it has,, in 
exceptional cases, been used as a fertilizer. It is now de- 
monstrated that hair from such stock is more valuable for 
all the purposes above referred to than when limed, and when 
the long haired hides are milled by themselves the hair will 
always pay the labor of saving-. For felting, all hair from 
hides unhaired by sweating, both long and short, is servicea- 
ble, and should never be wasted. 

The principal expense in saving hair heretofore has been 
in the drying. This is obviated by a very simple contrivance, 
as follows : Make a plank box eight or ten feet long, four to 
six feet wide, and say two feet high ; under a false bottom 
run a net work of steam pipe ; place the pipe midway be- 
tween the bottom and the latticed false bottom, so far dis- 
tant from each that a broom may freely pass to clear out the 
accumulating lime dust — and when thus prepared turn on the 
exhaust -steam from your nearest engine, allowing the steam 
to condense through this piping and under this false bottom. 



THE LEATHER MANUFACTURE. 153 

Hair may be thrown into this box to the depth of one foot, 
and will only require occasional stirring for an hour to make 
it thoroughly dry. In this way the hair may be dried read} 7 
for packing, while occupying but a small room space and at 
an inconsiderable expenditure of labor. 

Hair may be packed for transportation in bales, pressed as 
hay is (indeed, hay packing machines may be used for the 
purpose), or in sacks made of burlaps, as wool is usually 
packed. If pressed in bales, refuse boards should be placed 
on the bottom and top, and the whole bound with wire, pre- 
cisely as hay is now brought to market. When thus packed, 
fully 500 pounds can be placed in a bale four feet square. 

The water from the soaks, as well as the exhausted lime 
and bate liquor (including the wash from the hide mills and 
beam house), should all be collected together in a capacious 
reservoir situated below the level of the tannery foundation, 
so that all these valuable liquid manures may be brought 
together without the labor of elevating. This reservoir may 
be at any distance from the beam house ; indeed, it is far 
better to be removed a few hundred feet than close by. It 
should be capacious enough to hold not only the liquid 
refuse, but also all solids which come from the sweepings 
and scrapings of the beam house floor and drying lofts. 
So valuable are these washings that the writer has known a 
small tanner to fertilize a hundred acres by the refuse of a 
five thousand hide tannery. Old spent tan, fine chips or 
shavings, and even earth, maybe carted and thrown into this 
fertilizer reservoir, and allowed to absorb the ammonia, and 
then removed to the land, with great profit. 

A tanner with poor land about him, who allows his refuse 
liquids to run into the stream, is culpably thoughtless ; and 
yet such instances are numerous, notably so in the St^ite of 
Maryland, where the writer has seen hundreds of loads ol 



154 THE LEATHEK MANUFACTURE. 

the residuum of spent limes and bates piled up around the 
tannery. As the law forbade the tanner from throwing these 
objectionable substances into the stream, and as he owned no 
land, and was surrounded with shiftless farmers, large piles 
of the most valuable fertilizers remained to obstruct his way. 
The single tannery to which allusion is made could fertilize, 
if all liquid and solid matter of the beam house was distrib- 
uted, more than 400 acres of land. 



j* 



CHAPTEE XVIII. 

TANNING MATERIALS. 

DIFFERENT KINDS OF HEMLOCK BARK INFLUENCE OF SOIL AND CLIMATE 

ON THE QUALITY HEAVY AND LIGHT BAKK VARIETIES OF OAK BARK 

THE " SECOND GROWTH " BETTER THAN THE FIRST GAMBIER ITS 

GROWTH AND PREPARATION FOR MARKET — ITS COST COMPARED WITH 

THAT OF BARK VALONIA, DIVE DIVI, MYRABOLAMS " SWEET FERN,'"' 

ETC. 

On the American Continent, bark is the principal material 
for sole leather tanning, and although many attempts have 
been made to supersede its use, they have for the most part 
failed. The reasons for these failures are not very difficult 
to find, and should convince that large class of experimenters 
who rely upon " sweet fern," " salt," " alum," " terra japonica" 
and the like substitutes that the day is far distant when, 
in this country, any other substance than bark tannin will be 
successfully used for manufacturing leather. 

The tannin from hemlock bark, probably, tans eight-tenths 
of all the leather made in America, and notwithstanding the 
opinion entertained in England — and in this country too, by 
a few — that hemlock is inferior to oak, as a tanning material, 
the writer believes that, so far as the question is susceptible 
of demonstration, this opinion is erroneous. 

But to pass, for the present, from the consideration of the 
comparative merits of the manufactured article, and consider 
only the comparative cost and value of the bark as a tanning 



156 THE LEATHER MANUFACTURE. 

material, it should first be stated that there are two kinds 
of hemlock — white and red — and although there is a great 
difference in the timber of the two kinds, there is not much 
distinction in the tanning qualities of the bark. Some tanners 
think there is a dissimilarity in strength, and also in color, 
but the conceded difference between hemlock barks may be 
attributed to other causes than this difference of "species." 

Soil and climate we know influence the tanning qualities 
of all barks, and none more than the hemlock. All tamn 
know that hemlock bark from low, marshy ground, or the 
swales of the hills and mountains, is much thicker than from 
the high lands and mountains, and further, that a southern 
exposure produces more thrifty trees, and consequently 
thicker bark. The wash of the mountains, of course, feeds and 
enriches the valleys, giving richer soil and damper earth, both 
of which are indispensible to rank vegetable growth. It may 
not be generally known that all barks, like all woods, a 
made up of distinct layers or deposits, one layer being formed 
each year. This formation takes its character from the soil 
and the season ; if in rich soil and damp, wet surroundings, 
the layers will be thick, and "fat" with tannin, but if other- 
wise, the layers will be thin, and the tannin " lean." So uni- 
form and unerring are the laws governing these deposits, that 
naturalists claim they can not only tell the exact age of the 
tree, but they can determine with considerable accuracy the 
nature of the seasons through which the life has progressed. 
Assuming then that tannin is deposited just in proportion as 
the growth of the bark or tree is rank and healthy, we can 
easily see how it happens that in some sections of the coun- 
try a cord of hemlock bark will weigh 1,600 to 1,800 pounds, 
and tan but 140 to 150 pounds of leather, while in other 
sections a cord will weigh 2,200 to 2,300 pounds, and tan 200 
pounds of leather. These may be taken as extremes of qual- 






THE LEATHER MANUFACTURE. 157 

ity, but to find these extremes one need not go out of tin 
same neighborhood. The swamp bark represents the i 
extreme, and the high mountain bark, particularly if having 
a northern exposure, the other extreme; and yet, while this 
difference is known to all well-informed tanners, they con- 
tinue to pay the same price for each kind, and wonder why one 
cannot tan as cheap as another. But there is a further con- 
sideration which weighs against the light bark, audit is this : 
the small, stunted growth bark will curl, forming " gun bar- 
rels," while that from the heavy swamp timber will lie flat. 
This fact goes, to some extent, to make up the great differ- 
ence between the cord of 1,600 pounds and that of 2,300 
pounds, but the assumption of inferiority is outside and in- 
dependent of this disparity of measure ; if the premises are 
right, 2,000 pounds of heavy hemlock bark will tan more than 
2,000 pounds of light hemlock. Practically the difference 
cannot be very great, but so long as tanners continue the 
unjust practice of buying bark by the cord, instead of the ton, 
they will do themselves this wrong. The writer knows of a 
location where, for many years, the competition for bark lias 
been very strong; but one tanner, appreciating the difference 
above referred to, has always selected and purchased the lots 
of heavy bark, paying from one to four shillings per cord 
more than his neighbors, by which means he has, probably , 
paid less for the actual tanning material than any of his com- 
petitors. Why should one bark peeler be required t<> rank 
and draw 2,300 pounds from six to ten miles for the sa 
price that another gets for 1,000 pounds? The inju 
both to the tanner and bark peeler Jim--: I e very apparent. 
The light hemlock bark is supposed to imparl Less coloring 
matter than the heav}-. This is possibly true; indeed, it i^ 
so in the judgment of some of our best-informed Eastern 
tanners. Acting on this supposition, the fair Leather tanners 



153 THE LEATHEB MANUFACTURE. 

of Connecticut and Massachusetts continue to use the light 
hemlock obtained from the upper counties of Massachusetts 
and Vermont, supposing that the want of coloring matter 
will compensate them for the deficiency of strength. The 
beautiful lemon color produced by the Connecticut and Mas- 
sachusetts sheepskin tanners may be the result of the weak 
but pure liquors which they use, but if they subjected then- 
bark to the same heeding and leaching process as that of our 
sole leather tanners, possibly the difference would not be as 
great as is now imagined. However this may be, the sup- 
posed difference in the coloring matter of hemlock bark is 
keeping several large fair leather tanners in Connecticut from 
availing themselves of the cheaper hemlock of Pennsylvania 

and New York. 

To verify the theory here presented in regard to the quality 
of bark, let the reflecting tanner pass over in his mind, as he 
readily may, the whole tanning region of the country, com- 
mencing with Maine, on the East. There we find a cold 
climate, and for the most part a poor soil. The valleys of 
the Aroostook, the low lands surrounding Moosehead and 
other lakes, may be exceptions ; but generally these rich lands 
are covered with pine, and have only occasional patches of 
hemlock. The hemlock bark from that State is thin, and will 
not weigh, as bark is ordinarily measured at our tanneries, 
over 1,800 pounds to the cord. The same general character 
holds true of the bark of all the New England States. In 
the lower counties of the State of New York we have a 
warmer climate and a more diversified soil; where the soil is 
favorable we have thick bark, but the hills and mountains give 
us much thin bark. This is true of Northern and Eastern 
Pennsylvania also ; but as we proceed West and South in 
New York and Pennsylvania, the country is more open and 
level, the soil richer, and we have a more uniform and much 



THE LEATHER MANUFACTURE. 159 

thicker bark. Take those counties where wheat grows nat- 
urally, not merely on the river bottoms, but on the slopes of 
the highest hills and mountains — where you can see no "bar- 
ren wastes," as in Eastern and Central New York — and you 
are sure to find thrifty trees, with long bodies and thick bark 
— bark that will weigh 2,200 to 2,300 pounds to the cord. 

The effect of soil and climate on the growth and strength 
is still more apparent in oak bark. The bark from this tree 
is comparatively worthless in a cold latitude, while in Lower 
Pennsylvania, Maryland and Virginia, it is strong. There it 
grows on the bottom lands ; this, with the warm climate, 
gives the rank growth. But in New York the oak grows only 
on the hills and ridges, being crowded out from the swales 
by the hemlock, birch, beech, and maple, so that we cannot 
say what it might do under more favorable circumstances. 

It was suggested by the late Col. Pratt, and has been re- 
remarked by other observers, that sea air has something to 
do with the strength of bark. This observation, confined to 
oak, certainly seems to be verified by the known facts, for th< 
oak of Ohio, Michigan and the "Western States generally is 
very weak — scarcely strong enough, as now used, to furnish 
liquors of sufficient strength to preserve the hide from putre- 
faction. But may it not be that the oak of those States is of 
a different kind from ours? The writer has not seen n 
oak there, but has seen white oak and red oak of im- 
mense size and growth. This white oak bark is a poor tan- 
ning material, and the red oak but little better scarcely 
yielding enough tannin to pay for peeling. May it not be 
that the influence of sea air makes the difference bet v.. 

their oak and ours ? 

How many pounds of leather will a cord of hemlock bfl 
make? This question, a thousand times asked, has never 
been answered, and never can be, until a more c< rtain rule i I 



160 THE LEATHER MANUFACTURE. 

measurement is determined upon. As already hinted, if in 
a new location, where strong competition does not compel 
the tanner to take 90 to 100 feet for a cord, but where he can 
get 128 solid square feet, and that, too, of good, heavy bark 
(and the heavy bark is always peeled first, for obvious 
sons), then 200 pounds of leather can be made from one 
cord of bark ; but if these conditions are otherwise, then from 
130 to 150 pounds — and it is safe to say that throughout the 
old tanning districts of New York State 160 pounds is a full 
average. 

Little need be said of oak bark, for its merits are appre- 
ciated the world over. In this country we have the following- 
kinds: Rock Oak, (called by some "chestnut oak;") Yellow 
Oak (called sometimes "black oak," from the dark, black ex- 
terior, but by tanners called "yellow," from the fact that a 
very yellow color is produced by its bark;) Led Oak and 
White Oak. The first two are considered the most desirable. 
Their strength is about equal. The coloring matter, how- 
ever, of the yellow oak is so objectionable for sole leather 
that, unless used with red oak or hemlock, its value is very 
much impaired, but it is valuable for dj^eing purposes, and is 
exported from Philadelphia and Baltimore in large quantities, 
under the name of "quercitron bark." This bark (although 
of rather inferior quality) is found in large quantities in the 
State of New Jersey. 

White Oak makes a beautiful leather, but the tannin it con- 
tains is so small in amount as to render it almost worthless — 
certainty not more than half as valuable as the better de- 
scriptions of oak. The coloring matter, too, although very 
good of itself, is too weak to be of much value as a dye. 

Bed Oak is a heavy, hard bark to manage — difficult to 
grind, and heavy to handle — and when leached or used as a 
"duster," produces a "mean" red color, without the "fresh 



THE LEATHER MANUFACTURE. 101 

line" of the hemlock, or the "true bloom" of the oak, and 
would seldom be used for its own sake — but the wood is val- 
uable for staves, and hence the bark is peeled, and finds its 
way to the tanner, and, to his detriment, he is often induced 
to use it. 

The original oak — that is, the first growth, even of the 
best descriptions, is quite inferior as a tanning material; 
but the second growth — the young trees, say from fifteen to 
twenty-five years old, particularly of the rock oak — is very 
valuable, and, when properly blended with hemlock, makes a 
leather which, for color and wear, will compare favorably 
with the best tannages of the world. 

The effect of age upon the oak tree is to cause it to throw 
off a dead ross, which loses its tanning qualities ; hence, until 
within a few years, it was customary with all our oak tanners 
to ross their bark — throwing away as worthless fully one- 
third the substance of the bark ; but, after using up the old 
first growth, and coming down, as we now have, to the 
second growth, which has much less of this dead ross. the 
practice has gone into disuse. 

Oak trees reproduce themselves in about twent} r to thirty 
years, on good soil ; hence we may safely rely on a continu- 
ance of a supply. This circumstance, coupled with the favor 
with which mixed bark tannages are regarded, leaves no 
doubt that for all time we shall have a full supply of oak 
bark. Indeed, it has been estimated that more <>ak tannin i- 
now on the trees of Ulster and Greene counties than there 
was twenty years ago. Although this reproducing qua 
does not belong to hemlock trees, yet, in such abundance 
are they, both in New York and Pennsylvania, that many 
hundred years must pass before they heroine extinct. 

The curing of oak bark is an importanl subject, and is bul 

little understood — or, if understood, is but poorly attended 
11 



162 THE LEATHER MANUFACTURE. 

to. Fully one-third of the strength is lost in the careless 
cure, exposure to wet weather, piling damp, etc. The English 
pay as much attention to the cure of their bark as to that of 
their hay. The damage to oak bark, from improper exposure, 
is quite as ruinous as to hay, and yet our bark peelers give 
the bark only as much attention as their leisure will permit. 
The substitutes for hemlock and oak bark — the two prin- 
cipal agents used for tanning in this country — are very nu- 
merous. 

Gambier, or terra japonica, stands first and most prominent 
among the substitutes for bark, both in England and here. 
In 1840 the first "terra" was used in America, and only 
in small quantities, a few bales then sufficing to supply the 
market; now the import amounts to thousands of tons annu- 
ally, and its use extends to all the northern Atlantic cities, 
Newark, N. J., and Danvers, Mass., being the largest con- 
sumers. 

By a decision of the United States Treasury Department, 
gambier, catechu, cutch, and terra japonica, are all considered 
in commerce as essentially the same, but while they all come 
under the common name of terra japonica or gambier, a 
preparation of catechu, there are three different kinds of 
gambier, (in bales, cubes pressed, and cubes free), all of 
which differ in price from each other, and from what is 
known as cutch. The supply comes almost entirely from 
Singapore, in the East Indies, that island having become 
an entrepot in which are collected for exportation the pro- 
ductions of Cochin China, Siam, the Malayan peninsula, and 
the whole region of the Eastern Archipelago, from Sumatra 
to the meridian of New Guinea and the Phillipines. 

The product, as we receive it, is extracted from the leaves 
of a species of acacia, those from different parts of India 
giving slight variations in the quality. The shrub, or bushy 



THE LEATHER MANUFACTURE. 103 

tree, is grown from slips or cuttings, on plantations. It is 
cultivated and manufactured on land leased from the various 
Rajahs. The shrub is allowed to grow for the term of two i >r 
three years, till it attains the size of dwarf pear trees, when 
they commence to strip the leaves, stripping at all seasons of 
the year thereafter, for five or six years, until the soil is ex- 
hausted; the leaves come thickly on the long, drooping 
limbs, which grow outward and downward from the ground 
to the top. The leaf is in shape like the mulberry, but is 
thick and gummy to the touch. The production can be in- 
creased to any extent, and would, probably, if a long ruling 
of high prices should warrant it. The cost — the ground rent 
being nominal — is the labor, fuel and transportation, at the 
plantation not over 1c. to If c. per pound. 

The leaves are boiled to extract the gambier ; when re- 
duced to the thickness of molasses the leaves are raked out, 
being used for a land dressing about the pepper trees ; the 
water is then evaporated from the gambier by placing it in 
pans and exposing them to the heat of the sun ; later, after 
drying the gambier in these pans, it is cut into squares, form- 
ing cubes, which, when dry enough to handle, are bagged, 
sent to market (Singapore), screwed into bales of 2GG pounds, 
matted, covered with gunny, and is then ready for shipment. 

In the settiug out of the cuttings they are placed a near 
each other as will leave room for the shrub to grow. A n 
acre will produce 2,600 pounds annually, but it soon runs out 
the soil ; years ago it was mostly produced on the island of 
Singapore, but now very little is raised there. There 
several kinds or qualities, the Rhio being the besi ; it orig- 
inally came in baskets, in loose cubes, but lately. like the 
others, comes to market in bales. 

dutch and gambier are from the same or similar trees, but 
the two do not come from the same part of the country. 



161 THE LEATHER MANUFACTURE. 

Cutch is extracted from wood of the larger and older trees ; 
these trees are not cultivated, but taken naturally, the heart 
cut out, and from that the article known as cutch is extracted. 

But to pass from the consideration of the source and man- 
ufacture of gambier, let us consider it as a substitute for 
bark. In its pur e state it is largely used for dyeing pur- 
poses. The color is so dark and unsightly that tanners can- 
not use it — unless with yellow oak — without leaving a very 
objectionable color. The strength of pure gambier has never 
beeu appreciated in this country, aud, probably from the 
consideration above presented In England, on the con- 
trary, where oak bark is used with a " strong bloom," the 
color is overcome. 

Let me say here to the tanners of our country that gambier, 
m all its varieties, is an expensive substitute for bark. Hem- 
lock bark at $10 per cord is as cheap as gambier at 3,* cents 
per pound ; and yet the Newark tanners, with bark at $9 to 
$12, are using gambier extensively, with the latter costing 
from 5 to 7 cents a pound. The same may be said of the 
tanners of Danvers. Why this want of econonry? Because 
gambier comes in a form very convenient for use — can usually 
be bought in any desired quantity, at any season of the year. 
Its use prevents overcompetition for bark, and as the tanners 
are not quite sure that it costs them more than bark, they 
keep on using it, on the principle they do much of their busi- 
ness, viz.: "All is well that ends well." There is a day in the 
future when all this blind waste must give place to true 
economy ; and when that day shall arrive, perhaps to be 
hastened by the substitution of extracts from the barks of 
our own forests, then shall competition from England be no 
longer feared by us, but free trade in leather, as in everything 
else, shall best serve our interests, as it would certainly best 
comport with our self-respect. 



J*~ 



THE LEATHER MANUFACTURE. 165 

The exports of gambier from Singapore for the past si . : i 
years have averaged, for each year, as follows : 

To Great Britain 15,818 tons. 

To the Continent 3,930 tons. 

To the United States 4,818 tons. 

According to these lignres the amount taken by the United 
Stales has shown very little variation during the whole pe- 
riod. The amount used by Great Britain is supposed to be 
equivalent to about 60,000 cords of bark yearly. The price 
in London is now from £25 to £32 per ton. 

In Great Britain they have many other tanning agents for 
their heavy leathers, with which in this country we have so 
little experience that it would be presumptuous for the writer 
t > speak particularly of them. They are mainly valoni a, divi 
divi, myrabolams, etc. When the English tanner shall be- 
come as communicative as he is at present reticent, the 
whole world will be enlightened as to the comparative econ- 
omy of these agents with those in use with the t muers of the 
rest of the world. 

Valonia is the commercial name for the acorn cups of an 
Asiatic species of oak, which forms a very considerable art i 
of export from the Morea and the Levant. The cup only 
forms the valonia, the acorn not being exported. While k 
dry it presents a bright drab color; exposure to dampness 
makes it black and destroys its tanning properties. !i is 
very light and bulky, making the cost of i<s freightage high. 
It is very little used in the United States, but in Eugla'nd the 
imports are about 4,000 tons annually. The price in London 
is now from £15 to £18 per ton. 

Divi divi is a pod of a shrub, a native of South Am. 
and the West India Islands, the tannin of which is concen- 
trated in the rind of the pod, immediately beneath the epi- 
dermis; the inner portion, including the rind, is worth 



166 THE LEATHEE MANUFACTURE. 

for tanning. The leather prepared with divi divi h likely to 
be porous, and tinged with brown, or brownish red ; but little 
of it is used in this country. 

Myrabolams is the commercial name of the dried fruit of 
the mcluccanna, imported mainly from the East Indies. The 
imports at London for 1875 were 9,800 tons, against 11,200 
tons iu 1874, and 4,100 tons in 1873. The present price is 
fi-om £13 to £17 per ton. 

In addition to the above tanning materials — so largely used 
in England, and in combination one with another as well as 
with bark — 'he English tanners also use considerable quan- 
tities of Mimosa, Belgium and Cork tree bark, and are yearly 
taking constantly -increasing quantities of our hemlock 
extracts. 

Sweet fern is a tanning shrub or plant found on the barrens 
of most of the counties in the Eastern States. It has been 
extensively used in England, and to a limited extent in this 
country. The writer has been reminded by frequent circu- 
lars of various patents granted for the use of this plant for 
tanning. After reading the strong array of certificates in 
favor of the excellent quality of leather made from "sweet 
fern," by postmasters and other equally good judges, he does 
not dare to question the value of such patents. There is one 
point, however, to which the attention of all experimenters 
on these substitutes should be called. The question is not 
whether you can make tough leather with " sweet fern," su- 
mac and the like, but whether you can make the same or 
better weight. Can you make the leather with tannin so that 
it will both resist friction and water ? And more important 
than all, will the cost be less than with hemlock bark at $7 
per cord, or good rock oak bark at $8 per cord or ton ? 

That leather can be made from sweet fern, sumac, birch, 
chestnut, willow — indeed, almost all barks— and that various 



^ 



THE LEATHER MANUFACTURE. 1G7 

acids and salts will cure, or, if you please, fan leather, no on 
at all acquainted with the subject will dispute. Some of tin 
toughest, best working calfskins that were ever produced in 
our market were tanned with birch bark, and the color, too, 
was good; but they were tougL because the bark liquor was 
weak and the fiber, in consequence, elongated ; the weight 
and general plumpness were sacrificed to toughness. But 
when shoemakers, or even postmasters, certify that calfskins 
resist water better when tanned by these processes than when 
tanned by pure oak or hemlock bark, the writer is willing to 
believe them honest, but attributes a little of their zeal to 
kindness of heart rather than maturity of judgment. This 
subject is well illustrated by repeating a conversation held 
not long since with an old gentleman, who prided himself on 
knowing "a little about leather," as on other subjects he was 
wise. He said he always bought his calfskins of the " Shak- 
ers," for, said he, "they tan without steam," and "when my 
boots are made of their lightest calf, I can wade all winter 
through snow and water, and do not have even damp feet." 
The old gentleman meant to tell the truth, but probably he 
had not been in the snow and water without rubbers fi • 
years. Yet he succeeded in his purpose — he entered his 
protest against "steam tanning." It is thus that many peo- 
ple, from only a partial understanding of a subject, are free 
to give their opinions, upon which opinions too many, equally 
credulous, confide, to their cost. 

Many old-fashioned tanners, who have used only weak bark 
liquor, and for the first time tried terra, are astonished at the 
result. They tan as much in sixty days as by their old sys- 
tem they did in six months. The solution of the matter is 
plain; they make a strong decoction of the terra, one that 
will stand 20 to 25 degrees by the barkometer; whereas, by the 
old bark process, they were trying to tan v\itli (3 or 8 dej 



168 THE LEATHER MANUPACTURE- 

liquors. But let auy tanner take one hundred pounds of terra 
and dissolve in the usual way, and then take the strength of 
one cord of good oak or hemlock bark, and he will find the 
latter will tan double the quantity of leather that the former 
will. 

In this chapter the tanning agents employed in tawing or 
tanning light leathers have not been considered. The omis- 
sion has been made designedly, for the tanning and tawing 
of light leathers is a trade by itself, the treatment of which 
is not within the scope of the present treatise. 



CHAPTEK XIX. 
THE COST OF TANNING. 

THE SEVERAL ITEMS VARYING WITH DIFFERENT TANNERS DIFFEEENCES 

FROM UNEQUAL WEIGHT OF THE CORD OF BARK THE AMOUNT OF 

TANNIN IN UPPER LEATHER AS COMPARED WITH THAT IN SOLE LEA.THEB 

COMPARATIVE COST LN MAKING HEAVY AND LIGHT GAINS THE 

THEORETICAL STRENGTH OF BARK NEVER REALIZED COST OF " UNION " 

AND OAK TANNING ESTIMATED COST OF TANNING IN EUROPE. 

Approximately, the cost of tanning is as follows : 

Hemlock sweat sole leather ^ lb 6@ 7c. 

Union lime sole leather $(«\ 9c. 

Oak lime sole leather. 9(5 1 Oc. 

Oak lime rough leather 8@ ( .)c 

Hemlock lime rough leather 6(5 7c. 

The varying circumstances under which the tanners' pro- 
fession is pursued will cause the cost to differ within the 
limits above indicated. When a closer estimate is desired, 
giving the cost of each department, then a great diversity of 
opinion prevails. One tanner devotes ex tm time to the beam- 
house work; another to the finishing; still another f<> the 
handlers or layaways. If bark is cheap at one location, in- 
land freight and cartage is in excess of that at another pi 



170 THE LEATHEE MANUFACTUEF. 

where bark is dearer ; therefore, in stating the elements of 
cost, it is understood that an average is struck. These at- 
tempted details are of far less value than the general conclu- 
sions, which may be relied upon as above stated. 

One ton (2,240 pounds) of average hemlock bark will tan 
200 pounds of sole leather. Some of the exceptions are as 
follows : 1st. Where the bark is ground and leached imper- 
fectly, or in an extraordinarily perfect manner. 2d. If the 
leather is tanned with very strong decoctions, and thereby a 
very large gain is obtained, as against weak liquors and a 
light gain. 3d. Great delays and wastes in applying the 
tannin to the leather — delays which induce the formation of 
gallic acid, or the bringing of the fresh, sweet, strong decoc- 
tions into contact with liquor which has already formed a 
large proportion of acid. 

These exceptions cannot be always anticipated or known ; 
it is safe to say, however, that they vary the result all the 
way from 180 to 200 pounds of leather made from one cord 
or ton of bark. If tanners buy their bark by the cord, and 
get less than 128 feet solid measure — resulting, as often hap- 
pens, in getting 1,800 pounds, instead of 2,240 pounds for a 
cord — then, of course, such tanners will find the results of 
their tanning to vary still more. 

Among the topics above suggested there is but one to 
which attention will be now specially called, since on that 
one depends, far more than is generally supposed, the profit 
or loss of the tanner, i. e., the strength of the liquor employed. 

The upper leather tanners of New England, who pay from 
$10 to $12 per cord for their bark, claim to tan and probably 
do tan from 300 to 400 pounds of upper leather with 2,240 
pounds of bark. If we comprehend how this is possible, it 
will enlighten us as to the point under discussion. The up- 
per leather tanners draw their tanning and coloring matter 



THE LEATHER MANUFACTURE. 171 

from agents which furnish about 20 per cent, extractive ma- 
terial, while the vigorous sole leather tanner obtains his cap- 
ital mostly from the 7 to 8 per cent., tannin which the bark 
contains. The tannin gives all the gain added to the gela- 
tine, but the coloring matter permeates the fiber, while cumu- 
lative galiic acid holds it from decomposition. Upper lea t her, 
then, is not tanned and filled as sole leather is, and to this ex- 
tent, and for this reason, bark extract will spread itself over 
far more fiber when all the extractive matter is employed, 
than when it is so manufactured as to hold only the tanniu 
pure and simple. 

The calfskin and upper leather tanners of Garmany, Aus- 
tria and Switzerland make fully 400 pounds of rough stock 
from a ton of the best coppice oak bark, and where they use 
the " larch," corresponding to our " spruce " bark, they prob- 
ably make about 200 pounds (this bark having less than half 
the strength of the former). 

If upper leather and calfskins are to be sold by the pound 
(waiving the question of quality, especially toughness), then 
it is evident that these light tannages cannot be afford 1. 
But if sold by measure, then a light tannage is profii i 
for both the tanner and the consumer, under proper circum- 
stances. It is not proposed here to discuss the quest 1 
whether a light tannage will resist water. A tannage with 
an elongated and merely colored fiber will not carry stuffiu » 
when curried into upper, and will not resist dampness, and 
for these reasons such leather should not be used for the 
common wear of the people, whose feet are exposed to the 
varying conditions of the weather in our moist and we\ cli- 
mate. 

This preliminary discussion has been it" solve 

the question as to whether a sole leath I inner who tans by 
thp pound, and is not interested in the question of to 



172 THE LEATHER MANUFACTURE. 

can afford to make heavy gains for his employer. One tan- 
ner makes 160 pounds and another 175 pounds of leather 
from 100 pounds of the same description of hides ; are they 
entitled to the same pay per pound ? Is the cost to each pro- 
portionate? The argument on the one side is as follows : It 
costs a certain sum to work in, handle and fiuish a given lot 
leather, whether of a heavy or a light tannage ; the cost of 
the bark being alone considered, it cannot exceed and most 
usually falls short of the price received for tanning, even 
though that price is as low as six cents per pound. The 
sole leather problem is, then, in fact, but the upper leather 
question over again, which would ask and determine the 
following: Can a tanner afford to tan rough leather for less 
per pound than sole leather, less the finishing? It is no 
answer to say they do tan it for less, and it is not convincing 
that small yards in old tanning districts, without much in- 
terest to pay, are still pursuing this trade successfully. The 
argument on the other side is that heavy gains cannot be 
made without strong liquors ; strong decoctions cannot be 
obtained unless more or less waste is permitted — waste in 
the liquor itself, and more strength lost in leaching. Besides, 
the actual net added weight costs more than is received, 
which is calculated as follows : 

Original weight of hides 100 pounds. 

Less hair, grease, flesh, etc 15 pounds. 

Net gelatine and animal fiber 85 pounds. 

Now, whether this product is raised to 160 or 175 pounds 

is a question of mere intrinsic cost of the pure tannin which 

is capable of combining with the gelatine In the one case 75 

pounds is required, and in the other 90 pounds. The cost of 

these resp< ctive factors made from bark at $6 per cord would 

be (on the theory on which we are proceeding) fully 8 cents 

per pound, since in both cases we start with the hide capital 



THE LEATHER MANUFACTURE. 1~:\ 

of 85 pounds. It may be assumed that there is a discrep- 
ancy between the theoretical and practical percentage of 
tannin obtainable from bark. We know that 2,240 pounds 
of hemlock bark will make only 200 pounds of leather. 
Chemists tell us, however, that there is 8 per cent, tannin in 
this bark ; consequently there is in this ton of bark 156 80-100 
pounds, which, combined with 85 pounds of gelatine, should 
give 241 80-100 pounds of leather. What has become of this 
71 pounds of lost tannin? When any tanner will practically 
solve this doubt, then, and not until then, will the main 
question be answered. Practically, the cost of a pound of 
tannin is from 6 to 8 cents, and not 3 to 4 cents, as is gen- 
erally supposed. 

There is another subject nearly allied to the cost of bark, 
and that is the intrinsic cost of the oil put on sole leather. 
If the oil added gave full weight, then it could easily be de- 
termined whether it was profitable for the tanner to put on 
much or litt ! e oil. But, like the tannin just considered, there 
is much evaporation and loss, and the extent of interest in 
the final result of weight and profits must determine whether 
the tanner can afford to put oil on his sole leather at all, and 
to what extent. 

The cost of administration in a tanning establishment is 
always underestimated, and from this source, in the writer's 
judgment, many of the discrepancies result. A story is told 
of a young man who left his father's home to reside in the 
city of New York, promising to keep an accurate aci ount 
his expenses, and, with all his care, he found himself over- 
drawn more than $100 at the end of the year. To the in- 
quiry from his father as to the cause of this discn pi y. he 

said it must be " litterateur." The incidental expenses of Q 
tanning establishment are not less difficuU to defin . [f an 
attempt were made to properly apportion each item oi i 



174 THE LEATHER MANUFACTURE. 

pense in the production of leather, the factors of the total 
cost would be about as follows : 

Cost of bark (hemlock) per lb He. 

Cost of soaking, milling, sweating and beam work . . 1c. 
Yard worK, including handling, laying away, etc. . . . |c. 

Finishing, including drying, rolling, etc ^c. 

Insurance, interest on tanning and bark ^c. 

Freights to and from the market lc. 

Administration ^c. 

Total 7c. 

The cost of union or pure oak tanning will vary consid- 
erably from that of hemlock tanning where the hides are mi- 
haired by sweating, for, besides the added cost of bark, the 
extra care throughout the whole process, including the labor 
expended in the preparation of the hides, that are mostly 
green or green salted, will make up the difference, and the 
cost of the several kinds may be considered as stated at the 
head of this chapter. 

After the most diligent inquiry the writer has found it im- 
possible to even approximate the cost of tanning in the prin- 
cipal nations of Europe. A London tanner in 1873 estimated 
his tanning to cost 12 cents per pound in bark, and 10 cents 
per pound in terra japonica and valonia, but confessed that 
it was only an estimate. More recently a Bristol tanner cal- 
culated the cost of his pure bark tanning at 15 cents per 
pound, and even this is probably only an estimate. The 
cost of coppice* oak bark in the most favored locations is 
• net less than $25, gold ; and in most sections of Europe it 
runs up to $30, and even $40, per ton. On light tannages 
no doubt this bark will go a great way, but on butts and 
bends it may be assumed that foreign tanners use liquors 

* " Coppice " bark is from small trees, too small for timber, say six to eight inches 
in diameter ; also from limbs, equal to our " second growth " bark. 






THE LEATHER MANUFACTURE. 175 

of the highest strength. This is particularly true of the tan- 
ners of Great Britain ; perhaps it is not true to the same ex- 
tent of tanners on the Continent of Europe. 

The cost of all other material, including labor, is not 
greatly different in Europe from the cost here. The tanners 
of Great Britain pay about $1 per day for their average 
hands, while in other countries they pay, according to a re- 
cent authority, about 80 cents. But it may be fairly ques- 
tioned whether our labor is not more effective, especially in 
view of the increased amount of labor-saving machinery 
which we employ over some, if not all of our competitors. 



OHAPTEK XX. 
QUICK TANNING PROCESSES. 

COMMON ERRORS OF THOSE OUTSIDE OF THE TRADE HOW WORTHLESS PAT- 
ENTS ARE MULTIPLIED EXPERIMENT IN TANNING BY HYDROSTATIC 

PRESSURE VACUUM TANNING DIFFICULTIES ATTENDING THIS METH- 
OD — HOW AGITATION OF THE FIBER FACILITATES THE PROCESS A 

GENTLE MOVEMENT, WITH OCCASIONAL REST, MOST EFFICACIOUS 

TANNING VS. TAWING. 

It is noticeable that most of the attempts to substitute new 
for old methods of tanning are made by men outside of the 
trade. Very few of the new inventions for tanning, particu- 
larly those that contemplate the saving of time, originate 
within the trade itself. The inspiration of all this solicitude 
on the part of the outside world seems to come from the idea 
that tanning is a slow and tedious process, which needs in- 
vigoration by the genius of inventors and men of thought. 
They have "read history," in which it is claimed that seven 
years is the allotted time to tan butts and bends and make 
good leather, and that in this country we have only improved 
on this time by the introduction of " steam " and other 
" forcing expedients," which render the leather products here 
much less valuable than in Great Britain. 

There is do topic which requires more vigorous treatment 
than this, not only for the good of the trade, but for the ben- 
efit of that large and unfortunately increasing class of men 
who desire to get a living by their wits and without labor. 



THE LEATHER MANUFACTURE. 177 

As it is now our Patent Office gives encouragement to this 
class of parasites, for there seems to be no claim for im- 
provement too absurd to receive favor, and patents are mul- 
tiplied to such an extent that no man can keep an account 
of them. There are at present more than twenty patents for 
unhairing hides with alkalies, when the process of talcing off 
the wool from the sheep and the hair from the deerskin by 
hat d wood ashes is older than our civilization. What is most 
urgently needed in our Patent Office is at least one Examiner 
that has practical knowledge of the tanner's art. Such a se- 
lection it is not unreasonable to ask, when it is considered 
that this manufacture stands second in importance among 
the industries of the country. Proper discrimination would 
greatly aid improvements, while our present system confuses 
and retards meritorious inventions. 

Among attempts to facilitate the tanning of leather, per- 
haps no method or device has been more seductive than the 
forcing process known as the " vacuum " method. It is be- 
cause of its specious character that attention is here given to 
the details of its history and failure. Hydrostatic power gave 
birth to the first idea of tanning by pressure. " If," said a 
student at school, "I can raise myself with one quart of water, 
by means of a hydrostatic bellows, that principle can be 
availed of to force tannin into the pores of a green hide," 
and so the experiment was tried, in the following mann< r : 
A keg of very strong construction was procured, and a tin tube 
one inch in diameter was ran up through the lofts of a tan- 
nery to the bight of thirty feet ; the keg was filled with strong 
tan liquor, after a green prepared calfskin had first been 
placed in it, and then the tube was screwed on to the socket 
and also filled with liquor. The young tanner student had 
the satisfaction of seeing the liquor forced through the joints 
of the keg, and finally the keg itself burst, by the hydraulic 

12 



178 THE LEATHER MANUFACTURE. 

pressure caused by this small tube. When, however, the 
keg was burst open, the skin was found to be only colored, 
and the fiber no more permeated by the tannin than it would 
have been if the skin had been thrown into an ordinary vat 
of liquor for the same length of time. This experiment was 
repeated several times, for a longer period in each case, by 
applying the power more gradually ; but the result each time 
was the same. Tan could not be forced into the pores of the 
skin by surrounding it with liqnor under heavy hydrostatic 
pressure. 

The next experiment tried by this young student was to 
take a piece of prepared hide and place it under the exhaust 
pump. He had seen eggs expand and burst in a receiver, on 
exhausting the air which surrounded them. He had seen 
meat and dead animals expand and swell almost to bursting 
under a similar operation, and so, he reasoned, if he could 
place a hide in that condition, and produce that effect, and 
could, at the moment of the expansion, let in tan liquor — the 
result must be to force the liquor into the most interior cell 
of the hide, and, as Sir Humphrey Davy had demonstrated 
•that tannin and gelatine, when brought into contact, would 
both mechanically and chemically unite, he reasoned that 
such process of exhaustion of the air and swelling of the fiber 
must result in immediately tanning the hide, on the admission 
of the tan liquor. But such was not the result. The hide 
did not swell like other animal substances filled with air. He 
found that the cells of the hide were filled with water, and 
that water would not expand in any perceptible degree on 
account of the exhaustion of the air- 

A few years later an English engineer, who had through 
many years of his professional life practiced the art of pre- 
serving wood by kyanizing with appropriate chemical agents, 
conceived the idea of coming to this country and tanning 



THE LEATHER MANUFACTURE. 17'.) 

leather on this vacuum or kyanizing principle. He spent his 
entire accumulations, amounting to over $10,000, in con- 
structing a large iron tank in the shape of an egg, and lined 
this vat with copper. This tank was capable of holding one 
hundred heavy butts, and of resisting a pressure of one hun- 
dred pounds to the square inch. He provided himself with 
very substantial pumps to exhaust from this tank all the air, 
even to the extent of making almost a perfect vacuum, and 
other pumps to force in liquor, until he had obtained a pres- 
sure of 100 pounds to the square inch. Between these butts 
he had placed cocoa matting, so that there should be a per- 
fect circulation of liquor. In short, he prepared himself 
with every facility which money could procure to tan butts 
in a large and practical way by the exhaust or vacuum pro- 
cess, and after repeated attempts he failed entirely. What 
induced him to abandon his cherished enterprise was a small 
incident, which may throw light upon the subject for the 
benefit of those who yet see, or think they see, a defect in 
his method. In placing his butts in this egg-shaped vat, Ik 
found a space at the top which he could not fill with leathei 
and he placed there several blocks of seasoned wood, one f< x >1 
square. "When his experiment had ended and failed, after 
many anxious hours and days of trial, he found the wood 
perfectly saturated and tanned, but his butts were only col- 
ored through the grain. His conclusion was that the force 
that will kyanize wood will not tan leather. 

The name of the engineer was Thomas T. Ferguson, and 
the place where the experiment was tried was Sparrow- 
bush, Orange County, N. Y. The full details of fclie experi- 
ment were published in the Shoe and Leatheb IJi PORTEn 
some years since, it having been made about the year L855. 
Mr. Ferguson obtained patents in Great Britain and Prance, 
and applied for a patent here, but was so discouraged by 



180 THE LEATHEE MANUFACTURE. 

this effort as to abandon all further attempts at quick tan- 
ning. 

After these experiments had been tried and published to 
the world there came another experimenter, this time with 
an indorsement of a patent, by which leather was to be 
tanned in wooden tanks or vats that were far inferior, both 
in strength and construction, to the plan of the English en- 
gineer just mentioned, and many tanners have been induced 
to invest in the new process. So far as is known, however, 
the new quick tanning process has been a failure, and it 
stands so confessed by those most interested. 

The rationale of this whole matter of tanning by pressure 
from both surfaces has heretofore been greatly misunder- 
stood. The term "both surfaces" is used, for it is conceded 
that if force is applied to one side, and that the flesh side, 
the tan liquor will very readily pass, and tan the fiber with 
which it comes into contact. This is notably shown in the 
tanning of morocco and light leathers generally. A goat or 
sheep skin sewed up and filled with tan liquor will, by the 
gentle pressure of its own weight, tan in a few hours. A 
calfskin sewed up and placed where the keg was placed in the 
student's first experiment will tan in a few moments— that 
is, tan liquor will be forced through the skin, and the whole 
fiber will become colored, and even tanned. But it must be 
acknowledged that this pressure from one side is quite a dif- 
ferent thing from equal pressure from both sides at the same 
moment. Water or fluids of some kind fill the pores of the 
skin or hide, and these are not compressible, and in this 
lies the solution of these repeated failures. Water may be 
expanded by heat, but it cannot be perceptibly compressed 
by mechanical force or power. 

What would be the effect of forcing tan liquor from both 
surfaces into a hide that had no moisture or water in its 



THE LEATHER MANUFACTURE. 181 

fiber? Simply to " tan in " just so far as there was tannin to 
combine with the gelatine, while th.9 water in the liquor 
would pass on and fill the inner portion of the hide ; and 
then, before the process could be repeated, this water would 
be required to be pressed out by mechanical power or dried 
out by exposure to the atmosphere — and this alternate dry- 
ing and pressing process would be so tedious and withal so 
disturbing to the fiber that it would prove impracticable. 

It is not claimed here that under the recent vacuum pro- 
cess, so called, quicker time has not been made than by the 
older methods. The more frequent renewals of the liquors, 
the greater activity in handling, the agitation of the fiber 
occasioned by the alternate pumpiug out of the air and forcing 
in the liquors — these causes would naturally shorten the pro- 
cess, and are in themselves quite sufficient to account for the 
more rapid action of the tannin in combining with the gela- 
tine of the hide. But if, notwithstanding these experiments 
and warnings, tanners will insist on paying their money for 
patents that are worthless, no one should be held responsible, 
but our lunatic asylums should be enlarged. 

The supplement to Ure's Dictionary of Arts and Manufac- 
tures, at page 1044, contains an account of an invention for 
tanning in vacuo, patented by M. Knoederer, in Bavaria, 
which should be read by all persons contemplating further 
efforts ko avail themselves of this vacuo principle in tannin--. 
The account, apparently, is simply a statement made by the 
patentee as to his claim, and the results. There is nothing 
in either that is worthy of serious consideration, excrpi from 
the fact that the account has a prominent position in a woik 
of very high authority on general mechanica] subjects, and 
for this reason it attracts attention. It is noticeable thai in 
this process the sides or skins are passed under a mechani- 
cal press before they are put into the vacuo vessel. In this 



182 THE LEATHER MANUFACTURE. 

manner of preparing the stock, concession is made to the 
iact that water cannot be compressed. 

The writer has not desired to inveigh against the process 
of tanning by vacuum. If he had wished to show the com- 
parative expense of this method he would have gone into a 
calculation of the cost of the vats and machinery necessaiy 
to carry on such a system, giving the experience of some of 
those who have tried it — which shows that the vats made of 
plank and timber, and exposed to the air on their whole in- 
ternal and external surface, will decay in three years to such 
an extent as to require renewal — and so far as is known most 
of those who have tried the process have not renewed their 
vats after the first set lias given out. 

One of the most noticeable defects of vacuum tanning is 
one that has been experienced in tanning by suspeusiou in 
the ordinary open vats. The leather is " baggy " — that is, 
the nerve of the hide is tanned in its normal condition, and 
the shape of the animal from which the hide or skin was 
taken is approximately preserved. To overcome this defect 
it has been the custom of ihose tanners who tanned sole 
leather by this method to take the sides out of the vacuum 
vat and lay them away in the ordinary manner for a month 
or more. *. 

Whether sole leather is tanned by suspension in a vacuum 
or oidinary vat, the experience is that a much finer offal is 
produced than results from the ordinary handling and la} ing 
away. But the leather is neither so plump nor free from 
" bag " as if tanned in the usual way. 

It is claimed that ordinary slaughter sole leather, weighing 
eighteen pounds per side, can be struck through in from fif- 
teen to twenty days, if vigorously attended to, under the 
vacuum process. The leather is then taken out and laid 
away for thirty or forty days, when it is ready to finish. In 



THE LEATHER MANUFACTURE. JS.'l 

making this statement, and conceding all that is here claim 
what is the gain, either in time or quality? In ordinary tun- 
ning a daily strengthening and handling will bring this same 
leather through in sixty d lys, without the violent agitation 
ami expense attending this fencing process, and with better 
color and plumper fiber. 

The innovations upon old methods of tanning take upon 
themselves two general forms. They are either physical and 
outward, or chemical and latent. Of the former, pressvu v. 
either with or without the aid of the vacuo principle, has the 
greatest number of advocates. All, or nearly all, the chemi- 
cal agents employed in the shortening of the process turn 
out to be the old methods of tawing rather than tunning. 

It is noticeable that even the vacuo principle is greatly 
aided by the agitation of the fiber, for, by reference to the ex- 
periments of Knoederer, it will be seen that he tanned in 
about one-half the time when the leather was agitated in the 
vacuo vessel, over and above the time taken when there was 
nothing but the force of the vacuum to hasten the proc< -- 
The results are reported as follows : 

Time required for Time required 

tanning in vacuo when in ition 

without motion. is em] 

Calfskins. from 6 to 11 days. 4 to 7 days. 

Horse hides 35 to 40 days. 14 t«» 18 days. 

Light cow 30 to 35 days. 12 to 16 A 

Cow hides, middling. . .40 to 45 days. 18 I" 2 

Heavy cow hides 50 to GO days. 22 to 30 d 

Ox hides, light ........ 50 to 60 days. to 30 < I.i'n s. 

Ox hides, heavy 70 to 90 days 35 to 

Thus it will be perceived that motion or ngitation of 
fiber is a most essential promoter of quick tanning, even in 
vacuo. To this fundamental proposition .ill tanners cau 
•readily assent. When the advantages of motion or force, in 
the sense of agitation of the fiber, ;nv lu'.cn from the various 



184 THE LEATHER MANUFACTURE. 

patents which attempt to quicken the process of tanning, it 
will be found that there is very little left that has merit. 

The writer once tried the following experiment : He took 
four veal calfskins, which weighed eight pounds when green, 
and prepared them for the liquor in the usual way. He then 
tied the skins together and suspended them from the end of 
a spring pole, so adjusted that they were covered all the time 
by the liquor in the vat. For the first few hours the skins 
were agitated by means of this spring pole in a weak color- 
ing liquor, and were thus progressed from vat to vat until, 
at the end of the first day, they had reached a liquor of 16 
degrees strength. At the end of four days they were fairly 
and even fully tanned. This spring pole was so adjusted 
that a slight touch of the hand would set it in motion, and 
as each one who passed had instructions to "lend a hand," 
the pole was kept in motion almost constantly, with the re- 
sult indicated. This experiment should be tried by every 
tanner. It will attract his attention to a most important ele- 
ment in quick tanning. If the experment should prove as 
interesting as it did with the writer, it will lead to other re- 
sults and conclusions. It will indicate that a most delicate 
touch will agitate sensibly the fiber throughout the whole 
skin or hide; that gentle motion is most efficacious, and that 
violent motion is positively injurious, as the latter purges the 
cells of their gelatine and prevents the plumping and final 
gain in weight. 

The relative influence of gentle and violent motion on lea- 
ther when in the handlers has been demonstrated by the ac- 
tion of the " rocker." Here, with the most delicate and uni- 
form motion, it is found expedient to discontinue the move- 
ment altogether for a considerable portion of the time, other- 
wise the sides do not plump and take on a uniform grain, 
whereas by only sufficient working the most desirable result 






THE LEATHEE MANUFACTURE. 185 

in these particulars is obtained. Many mistakes have been 
made, and much damage done through a misunderstanding 
of the action of liquor on the fiber, according to this princi- 
ple. Fifteen or twenty lifts or turns per minute are ample, 
and these should be continued only about half the time. 
Besides giving rest to the fiber, this slow motion does not, to 
the same extent that a quick, violent motion does, turn up 
the liquor, bringing it into contact with the ah', thus causing 
gallic acid to form. 

These experiments, if carefully made, will also convince 
the tanner that the gelatine of the hide has such an affinity 
for the tannin that they combine much more readily than is 
supposed ; this is made apparent by the rapidity with which 
the tannin is taken up while in the rocker vats. Once let a 
tanner be satisfied that his green stock is hungry — constant- 
ly demanding nourishment — but without the voice to make 
known its wants, and his financial sympathies will hardly 
ever allow him to sleep without the apprehension that he is 
neglecting his most vital interests. 

Knoederer claims, and with some show of reason, that his 
vacuo process prevents the formation of gallic acid, and to 
this extent all methods that tan under liquor, in such manner 
as to avoid exposure to the air, either of the liquor itself or 
of the pelts that are in the process, should receive favor. 
Further than this, the method of "throwing up" the packs, 
it is claimed, presses out the spent liquor and prepares the 
vacant cells to receive an infusion of newly charged t.-m 
liquor. Aside from the disproportionate labor imposed by 
the old over the newer methods, the writer believes thai the 
action of the atmosphere, both on the color of the Leather 
and to cause oxidation of the liquor, must prove a sufficienl 
demonstration of its impolicy. 

Leather tanned while in a composed state (at will 



186 THE LEATHER MANUFACTURE. 

have a firmer texture than if motion is used to aid the tan- 
ning. This would probably be the testimony of the butt and 
bend tanners of Great Britain, and there is much in our own 
experience to confirm such a view of the case. But the ques- 
tion under review is one rather of time than of firmness of 
texture. None of the advocates of improved forcing methods 
claim, so far as the writer is aware, that they make firmer 
leather. They usually assume to make better time, and ex- 
ceptionally claim better gains. Their improved giins they 
estimate to come from the saving of the waste of the gelatin •, 
by reason of its earlier entering into combination with the 
tannin by their quick as against the older and slower methods. 
The best experience in America would direct that, after the 
hide is "struck through" by the most rapid combination possi- 
ble, it be "laid away" for a period uf weeks and even months 
— all the time in which its firmness of texture will improve. 
But if it is only required to taw (that is, strike through) the 
fiber with tannin and coloring matter, then the handling or 
fiber agitating methods are alike ; for harness, upper and 
even calfskins this process gives very fine offal, and makes 
most serviceable wearing leather. 

Hardly a month passes that some restive spirit does not 
discover, for the hundredth time, that salt and some of the 
sulphates, notably the sulphate of alumina, known in com- 
merce as alum, and potassa, will in various combinations 
tan, or, more properly speaking, taw or preserve, hides and 
skins, which, after being "mooned," will make a very tough 
and serviceable upper leather. In this manner glove and 
calf-kid leather is made in a most artistic manner, and on the 
Continent of Europe the latter description of lea'her enters 
very largely into the consumption of the people for wear in 
shoes of both men and women. For dry and warm climates 
hardly anything more desirable could be obtained, and as it 






THE LEATHER MANUFACTURE. 187 

is made at much, less cost than bark tanned leather, then 
an excellent reason why the ca]f, goat and sheep skins of 
those countries should be so manufactured; but when thi 
tawing processes are applied to making sole leather in this 
country, which abounds in bark, the tannic acid of which 
combines w r ith gelatine, and is when so, combined not soluble 
in water, then all effort in that direction is just so much 
wasted force. 



CHAPTEE XXI. 
THE SPECIES AND GROWTH OF HIDES. 

" HEALTHY " AND " WELL GROWN " HIDES DIFFERENCES LN HIDES AT VA- 
RIOUS SEASONS OF THE YEAR EFFECT OF CLIMATE AND FOOD ON TEX- 
TURE AND GROWTH IMPROVED BREEDS OF CATTLE MAKE HEDES THIN 

AND SPREADY COLD CLIMATE MAKES A COARSE FIBER AND WARM CLI- 
MATE A FINE TEXTURE EAST INDIAN, AFRICAN AND SOUTH AMERICAN 

HIDES THE HIDES FROM THE EASTERN AND MIDDLE STATES AS COM- 
PARED WITH THOSE FROM THE WESTERN PRAIRIES CARE TAKEN OF 

CATTLE IN EUROPE. 

In a previous chapter reference was made to the structure 
of hides, but for quite a different purpose from that which in- 
( Uices the treatment of this subject here. The bison, the sheep, 
the deer and the goat belong to species so different from the 
ordinary neat cattle that no one would think of comparing 
their merits or defects, although the designation of "growth" 
will apply to all alike. A sheepskin can be a "healthy pelt" 
and "well grown" no less than the hide of the ox or cow. 
In this chapter, then, wall be considered the species of cattle 
and their growth, in the sense in which we speak of health 
in the animal and vegetable world ; not that all animals or 
vegetables are alike, but only that the} r have their distinctive 
natures, and are well or id within those limits, according to 
the seasons and circumstances through which they pass. 

The English tanner must be credited with the first appli- 
cation of the term "growth" as applied to hides. He would 



THE LEATHER MANUFACTURE. 180 

formerly have said a hide is "well grown" when it was 
healthy, plump and fine — whether it was a bison hide from 
the Western plains of North America, or a Spanish ox hide 
from the pampas of South America; but from this original 
and more correct designation the English tanner has come of 
late to speak only of plump, thick hides as well grown, and, 
as the term is thus used, only such hides as are suitable for 
butts and bends are called " well grown hides " in England. 
But, to use the term in a less restricted sense, the hide is 
well grown in the American tanner's view when it takes on 
its highest and most perfect nature, and then the designation 
applies to all hides and skins alike. 

We have spring, summer, fall and winter hides, and these 
adjectives have to the tanner a most distinct and qualifying 
meaning. The hides of all our neat cattle in the spring of 
the year are thin, and frequently have grub holes in the 
shoulder and on the hue of the backbone. In early sum- 
mer the cattle begin to recover, and by late in Jane they 
have shed their hair, though while the hide is healthy the 
full growth does not come to it until September and October. 
The hides taken off at the latter season are thicker and 
healthier than those furnished at any other period. At the 
approach of cold weather the hair becomes long, and the 
hide, by sudden contractions and expansions, loses that firm- 
ness so desirable for butts and bends. 

The influences, also, of climate and food, quite independent 
of the health of the animal, have a controlling effect in de- 
termining the value of the hide. As an illustration of the 
effect of climate on the fiber, the hides from Canada and 
from Kussia are far coarser in texture, and for this reason 
are less valuable, than hides from the United States. Their 
winters are longer and much more severe than \\ i(l> as. This 
is true even when the cattle arc the same in Bpecies. It is 



190 THE LEATHER MANUFACTURE. 

for this reason, and from this cause in part, that the Spanish 
hides of South America are better grown, both in the Eng- 
lish and American sense, than are the hides of our States. 
The extremes of weather we have are never experienced 
there. The cattle feed on evergreen pastures, and are 
never housed, as with us. The cattle of Texas are of 
precisely the same species, and even of the same breed, 
as those of Buenos Ayres, and yet, intermediate between 
these, we have the cattle of the Rio Grande, of the sanie 
species but of a different breed, whose texture is far coarser, 
showing that climate and food cannot wholly control the 
structure. 

The improved breeds of cattle which have been introduced 
both in Europe and here have done just so much to make 
the hides thin and spready. The improvement induces a thin 
skin. A "blooded horse" has a thinner skin than the old 
farm or plow animal. So noticeable is this that the English 
tanner has long since given up the idea of getting butt bides 
from domestic cattle. The cattle of Spain and Portugal, be- 
ing of the unimproved original stock, give the English tanners 
the only slaughter butt hides they have. In this country we 
are fast improving all the plumpness out of our hides, and it 
will be only a few years until we, too, shall depend upon Tex- 
as and South America for all our thick pelts. 

If a cold climate induces a coarse fiber, then it should he 
true that a warm climate makes a fine texture, and this we 
find to be in accordance with the fact. The hides of Africa 
and Central America have a fine texture beyond any other of 
which we have knowledge. The texture is not seemingly 
so much affected by food as by climate. The great droughts 
of these tropical regions do not to any perceptible extent 
control the texture, but they do affect the growth. This is 
illustrated b}- the conceded fact that the cattle of Texas that 



THE LEATHER MANUFACTURE. 101 

are known to die of starvation retain a fine textured hide. I ' 
it be said that the animal died before it had time to change 
the fiber or texture of its hide, this is not true of the growth, 
for the hide contracts and becomes diseased with the decay 
of the body. The same is true of a murrain calf or kip skin. 
The fiber is really closer and finer than that of a vealskin. 

It is, then, probably true that where the species and breeds 
of cattle are the same, food affects the growth and climate the 
texture, and the experience of those who should be the best 
judges confirms this conclusion. 

The "East " and " Y/est Coast" African hides are so radi- 
cally different that it may be assumed the East const hides 
are from cattle brought from the Island of Madagascar, and 
still more remotely from Hindostan and the Chinese Empire. 
The hides from the West coast, bordering on the Atlantic 
are substantially the same as those from our cattle, only 
dwarfed by imperfect food and culture. Australia, on the 
other hand, shows more direct signs of contact with Greai 
Britain, whose colony she is. The cattle and hides from tlii- 
province, although produced under the same climate as that 
of many other islands of the Indian Ocean, are distinct in 
character from all the rest, and when made into leather may 
pass for the hides of well grown neat cattle, equal to tf 
of Great Britain or the United States. But the hides from 
the smaller groups of islands lying in the same ocean, ;i^ 
well as from China and Japan, are for the most pari Erom 
cattle that are popularly known as Easl Endia cattle, so small 
in frame and delicate in outline, as compared with our cattle. 
a; to have received the designation of "kips" rather thai 
hides from full grown cattle, as they are. This designation 
covers that large class of East India kips from which British 
tanners make a most serviceable lighl upper leather, and th< 
imports of these kips at London and Liverpool amount to 



192 THE LEATHER MANUFACTURE. 

about five millions yearlv. The cattle from which these 
hides are taken are quite uniform, and when full grown about 
the size of our yearlings, but are much more delicate in limb 
and feature. 

The part which this East India hide product is to play in 
the future supply of the world is as problematical as the 
question which is now agitating our country about the labor 
supply from that quarter. When we bring ourselves into new 
and friendly business relations with 400,000,000 of people, 
ojcupying a vast territory, and with a diversified climate 
and soil, we may well hesitate about our conclusions — and 
this Centennial year joins us to China and Japan by ties 
more close and direct than it has been the fortune of any 
of the nations of Northern and Western Europe to enjoy 
through all their previous intercourse. 

The influence of climate also finds a notable illustration 
in the character of hides and skins taken off in the new 
Prairie States of our own country. All concede that the 
species, and even the breeds, are the same as with us in New 
England and the Middle States, and yet the texture of their 
hides and skins is much coarser ; particularly is this true of 
the calf and kips of those States. The reasons for this con- 
ceded fact are as follows : The cattle are seldom housed, even 
in extreme winter. The farmers have no barns, or even pro- 
tecting sheds, and the cold so overcomes the cattle as to 
seriously affect their growth. This may be noticed in their 
calves. A calf dropped by a cow in the Prairie States will 
hardly stand on its feet until eight or ten days old, while at 
the East they will caper and play within twenty-four hours. 
The calf from a well-cared for cow, at the East, will mature 
and its meat may be eaten in three or four weeks, while at 
the West from six to eight weeks is required. This same 
want of strength and growth is as observable in the pelt as 



THE LEATHER MANUFACTURE. 193 

in the meat. The difference between the "drop" or "dea- 
con " skins of Ohio and those of Northern New York should, 
according to the theory heretofore given, be in favor of those 
of Ohio, for there is fully five degrees of latitude against 
New York, but with us the cattle are carefully housed dur- 
ing the fall and winter months, and this care more than com- 
pensates for the difference in climate, and results, as all tan- 
ners fully understand, in giving character to the calf pelts of 
the respective regions. 

In accordance with this perhaps too hasty conclusion in 
regard to the effect of care and culture of the neat cattle 
upon their offspring, the question arises whether th<* conceded 
fineness of texture and perfect growth of the G-ernian, French 
and Swiss calf may not in some measure be attributed to the 
almost humane care which is bestowed in these countries 
upon their domestic animals? And if this fineness of tex- 
ture extends to the skins of the offspring, may not the hide 
of the parent animal be measurably affected ? These may be 
mere speculations, but they are based upon considerable ol i- 
servation, and have received the sanction of cattle breeders 
of much renown. The cows of Holland occupy the warmest 
and best portions of the family dwelling, and are cared for 
with as much tenderness as any of the inmates. It may be 
said of the domestic animals of all Central and Southern 
Europe that they are cherished and cared for in a mueh 
larger measure than the human family, supposed to be their 
lords and masters. May not this culture and care have somi 
thing to do with that superior growth and texture which 
seems to characterize their calf, goat and sheep skins '! Tin's 
discussion may be too general to satisfy tanners that breeds, 
climate and food control the value and qualities of hides and 
skins, and yet they must admit that the theory lie re broache I 
is in accord with common observation. 

13 



CHAPTEE XXII. 
FRENCH AND GERMAN CALF AND KIP. 

WHERE OUR IMPORTED STOCK COMES FROM CAREFUL ASSORTING OF THE 

RAW STOCK TO INSURE UNIFORMITY IN WEIGHT, SUBSTANCE, AND GEN- 
ERAL CONDITION SOAKING AND MILLING — BREAKING THE NERVE 

LIMING BATING AND WORKING OUT LIME COLORING AND HANDLING 

—LAYING AWAY AFTER WORKING STUFFING DRYING SLICKER 

WHITENING BLACKING AFTER THE STOCK IS CUT OUT USUAL IN 

EUROPE VEGETABLE OILS USED INSTEAD OF FISH OILS DEFECTS IN 

FOREIGN CALFSKINS — STEADY IMPROVEMENT IN AMERICAN CALFSKINS. 

In what is here said of French and German methods of 
tanning and finishing calf and kip skins, the statements may 
be regarded as applying also to the production of this class 
of stock in Switzerland and Austria. Indeed, contrary to 
the general impression on this subject, these countries are 
about equally represented in the manufacture of this descrip- 
tion of light imported stock, commonly styled by consumers 
"French" goods. We seldom hear of "Swiss" calfskins, 
although Mr. Mercier, of Lausanne, Switzerland, is the 
largest manufacturer sending leather to this country. The 
common designation of " French," as applied to all imported 
skins, arises from the fact, probably, that American agents 
for the purchase of these skins reside mostly in Paris, and 
ship largely through French ports. This consideration is 
important in this connection only as showing that a charac- 
teristic and almost uniform system or method of manufacture 



THE LEATHER MANUFACTURE. 195 

prevails in all the countries mentioned, and the goods they 
produce may, therefore, be treated as one manufacture. 

There is one other preliminary consideration which should 
be hare stated, viz., only the best goods of manufacturers on 
the European Continent are sold to this country or to Great 
Britain— that is, only those parties that manufacture calf 
and kip as a specialty, and in large quantities, ever think of 
selling their products away from home. Of the ten thousand 
and more tanners of these countries probably not more than 
fifty find a market in the United States for any considerable 
portion of their stock. The local or country producers of 
calf and kip in all these countries labor under the same dis- 
abilities as do the large number of small tanners in our own 
country. They are not able, from their limited faeilil: 5, 
either to obtain skilled labor or to make the same selections 
as do those tanners who make a specialty of this class of 
goods, and do the business in a large way, and hence it is 
that the people of Continental Europe generally wear no more 
artistic calf and kip than may be found in the shoes made 
up for the ordinary wear of a large portion of our own popu- 
lation. 

Li respect to weight, substance and general condition, the 
skillful foreign tanners take especial pains to see thai the 
skins of each pack shall be as nearly alike as possible. In 
this respect their practice does not differ from the theorj of 
our largest and best calfskin tanne rs, but by reason of the 
large unmanufactured stocks which they nsually carrj they are 
enabled to put their theories into practice more thoroughly 
than it is possible for our tanners to do. Their calfskins are 
for the most part dried without salt and folded on the back ; 
the selections for weight are then made, and the skins 
packed in bales. This is done bythe factor or dealer. When 
the goods reach the tanner he still further assorts and 



10G THE LEATHER MANUFACTURE. 

packs them away in cool lofts where they await his want?. 
How different these circumstances from those presented to 
our large calfskin manufacturers, who buy all their stock in a 
green salted state from the 1st of May to the middle of July ! 
The condition of the green salted skins as handled by our 
tanners taxes their best energies; to keep them from salt 
pricking and decaying is very difficult, and the tanner is 
forced to hurry them into the tanning process with indis- 
criminate haste. 

When skins in all respects alike go into the soak, they are 
equally affected by the water, and are ready for the mill at 
the same time, thus enabling packs that are commenced to- 
gether to go through to the end without separation or divi- 
sion. This uniformity also greatly aids the general economy 
of the manufacturing by keeping the tanner informed of the 
amount of product which he is realizing from his raw mate- 
rial, for each pack or series of packs will indicate to him his 
loss or profit. Aside, however, from the general merit of this 
classification at the start, it may be asserted confidently fiat 
no tanner can make uniform and good stock without such 
selection, even with the greatest care in the after handling. 

The treatment necessary at this stage of the process will 
be greatly influenced by the condition of the stock. If the 
skins are green salted, as with us, a very slight milling will 
suffice ; but if they are flint dry, as with some of our small 
tanners, then they should be thoroughly softened. But any 
forced softening must be preceded by a certain amount of 
soaking, which in turn will greatly depend on the condition, 
whether green, green salted, dry salted or absolutely flint dry. 
The soaking process will, therefore, extend from a few hours 
to a few clays, depending upon the condition of the skin and 
the state of the weather. If the skins are flint dry, they 
should not be milled until after ample soaking, and even hand- 



THE LEATHER MANUFACTURE. 197 

ling i;i the soak; but the first milling should be gentle, other- 
wise the grain of the skin maybe cracked. This mil' 
should be only for a few moments, and with a full mill, s i 
that the large body of skins will present a soft, yielding 
mass to the action of the hammer, if the softening be 
accomplished with the ordinary fulling stocks. If a revolv- 
ing wheel is used, then the same care is necessary that 
the skins may not have too violent a pounding on the inside 
wooden projections. After the first slight milling the pack 
inaj again be returned to the soak or thrown up in piles. 
The action of the water in the second soaking will be nmch 
more rapid, and great care should be taken that the grain 
does not " prick." After the pelt has been in this manner 
made as soft as water and ordinary milling will accomplish, 
then we notice the first peculiarity in the methods of the 
French and German tanners, as compared with the practice 
here, which consists in the thorough breaking of the nerve. 

The nerve to be broken is a description of interlacing fiber 
which holds the animal tissue. This nerve is located tr.i 
versely on the flesh of all pelts. It may almost be said to 
make a part of the flesh itself, and lies immediately under 
that loose, fleshy tissue which curriers shave off before they 
reach the pelt proper, on which they form their wa ted sur- 
face. The office performed by this nerve or tissue is, by its 
contraction and expansion, to hold the pelt close around I 
animal. It forces the pelt to conform its shape to that 
the animal whose body it covers. When the animal is fal 
and well rounded out it expands, and when poor, sick, 
or thin, it contracts. It is this nerve which induces "bag- 
ging" in all leather, notably in solo leather, while in ban* 
and upper leather, which is stretched by shaving and scour- 
ing, much of the contracting force of this nerve is destroy* d. 
But something more and beyond the avoidance of " bap 



198 THE LEATHER MANUFACTURE. 

is required in the preparation of calfskins. The nerve mast 
be so completely severed or broken that the whole pelt will 
feel not only soft, but actually pulpy. This effect can only 
be produced at present by hand labor. No machine has 3-et 
been devised to do it, although it may be predicted that, 
when the great utility of the work becomes appreciated, a 
labor-saving machine will come forth from the brain of some 
American to perforin this labor. The hide-working machine 
of Mr. Henry Lampert, of Rochester, N. Y., when improved, 
may answer the purpose, or suggest the way to some other 
and better machine. 

If the skins are dry or dry salted there is no difficulty in 
determining when this nerve is sufficiently severed ; but if 
they are g. en or green salted, unless more than the usual 
care and conscientiousness is exercised on the part of the 
workman, the nerve will remain unbroken, and will hold the 
whole fiber of the pelt firmly during the entire after tanning 
process, so that it becomes difficult if not impossible ever 
afterward to make a yielding and elastic substance from the 
skin thus treated. 

Assuming that we have succeeded in breaking this nerve, 
and have brought the pelt to a soft, pulpy condition, the 
next process will be liming and unh airing. The skin has 
been brought to a condition in which it will readily take the 
lime, and four or five days in a moderate lime water will neu- 
tralize the animal grease, and soften and swell the roots of 
the hair so that the latter will come off with the most incon- 
siderable labor. No more lime need be used than sufficient 
to accomplish these two objects, although the practice in this 
respect is not uniform ; the statement is made rather on a 
knowledge of the American experience than from personal 
observation as to the practice of foreign tanners. 

When the hair is removed the skins should be thrown into 



THE LEATHER MANUFACTURE. L99 

the mill or wheel and washed for a few moments. If in warm 
weather, water at a temperature of 60 degrees should !><> used, 
but if the weather be cold, the removal of the lime will be 
greatly facilitated by using water a temperature of from 80 
to 100 degrees. This warm water and milling process must 
be conducted with judgment and care, but when so carried 
on it is perfectly safe, and considerably shortens the process 
of depletion, besides saving the expense of other depleting 
agents, usually called "bates."* 

The lime must be worked out before the skin goes to the 
handler. In the practice of some of our American tanners, 
the acid of the liquor is relied upon to overcome a portion of 
the lime which may not be readily removed, very much as is 
done by some of our sole leather tanners ; but, according to 
the best French process, the lime must be thoroughly worked 
out before the skin goes into the handlers, and all the work- 
ing is done on the grain rather than on the flesh side. The 
result of this treatment is that the skin, when properly pre- 
pared for the handlers, is so depleted that the pelt of an 
ordinary eight-pound green veal skin can be drawn through 
a ring two inches in diameter. 

After all that has been said or experienced by tanners, it 
is probably true that much depends on the kind of liquors 
which are applied in the handlers. Skins depleted by bates 
in the ordinary way, and subjected to sweet liquors in the 
handlers, will, undoubtedly, give a finer flesh and a tougher 
fiber than when otherwise treated, but whether the skin will 
be as plump and as full in the offal may well be doubted. 
If, however, there is any lime left in the skin, sour or aeid 



*Some of the best and largest tanners of Switzerland d( pen I vei ■ on 
the sour acid liquors of the "larch" bark, both to form their color nn i at the 
same time deplete the skins. One of the mi 111 calfskin tanni 
Switzerland told the writer that he did not consider il lepleto with ordi- 
nary bates, and then trust to sweet liquors I lor and tan !; 



200 THE LEATHER MANUFACTURE. 

liquors must be so far used in the coloring and early tanning 
process as to overcome the last particle of lime, otherwise 
the tanner will have a coarse flesh and spongy fiber that will 
not " carry " stuffing in the finishing process. 

The methods of coloring and handling followed by the tan- 
ners on the Continent of Europe, so far as they came under 
the observation of the writer, w T ould probably fail to give sat- 
isfaction to American tanners. The handling there is done 
in vats, with old sour liquors, replenished with either "larch" 
or partially spent " oak " tan bark. About one-half of a pack 
is put into a round or square vat, and a man is constantly 
employed in raising the skins to the surface by means of a 
pole, very much as was the practice of our tanners fifty years 
ago. Other tanners, more advanced and doing business in a 
larger way, have a revolving wheel in the top of their vat, 
constructed and operated very much after the style of our 
so-called " England " wheel. 

The process of merely coloring and handling soon termin- 
ates, and then the skins are paired and laid away, grain to 
grain. The object of this grain to grain laying away is two 
fold — first, to tan the skins from the flesh side ; and, second, 
to keep the grain smooth and tough. Both of these objects 
are accomplished by this process, and, next to the breaking 
of the nerve in the beam house, this may be considered the 
most important innovation upon our method. The skins are 
paired according to size, and carefully laid pate to pate and 
butt. and butt, a matter which is not difficult in a pack that 
has already been selected with great care to secure uni- 
formity in weight and substance. A man will size and plr.ee 
these skins grain to grain almost as fast as he could handle 
them in any other way. When so placed and held by the 
i-kind shanks with both hands, they are passed to a man in a 
-deep round vat, from which the liquor has been drawn. This 



THE LEATHER MANUFACTURE. 2^1 

man first takes a shovel full of spent or partially spent bark 
from one attendant, and then a pair of skins from another, 
laying first bark and then skins, and thus alternating until 
the tank or leach is nearly filled, walking around on and 
packing down both skins and bark, taking care to fill up all 
intervening spaces with bark. These vats are usually round, 
being six to eight feet deep, and eight to ten feet in diameter, 
about ten times as much space being occupied with bark as 
with skins. When the vat is filled to within a foot of the 
top, water or old liquor is run on until a covering is obtained, 
and this first layaway is continued for from ten to tin it \ 
days. The second, third, fourth, and even fifth, layaways 
follow at intervals of from twenty to forty days, each time, 
however, with more of an admixture of fresh strong bark 
with the old and partially spent tan, and with an increased 
strength in the liquor run on, but so far as the writer has 
observed no new bark is leached and the decoction resulting 
put on the packs. 

The result of this practice is to tan or color through the 
stock in four, six or eight months, and this is done from the 
flesh side mainly, the grain of each skin being at all tim< a 
covered and protected by the grain of its mate, without any 
bark or bark liquor intervening. The effect of this cl< 
proximity of animal fiber is to prevent anything like the 
formation of old grain, and where such grain docs form i\ Is 
so soft and yielding as to be readily "pulled out' or 
"boarded out" without scouring in the process of currying. 
The grain, when the skins are first separal ■<!, indicates jusl 
such a condition or appearance as would the -ruin on a pack 
that had been allowed to sweat in piles, but as the grain sur- 
faces have been absolutely excluded from Hi* 1 air during the 
whole process they are without stain, of the most delicate 
color, and extremely fine and pliable. 



202 ■ THE LEATHER MANUFACTURE. 

The tanning processes being completed, the bark is thor- 
oughly shaken out as the skins are taken up and laid in piles 
to drain and "sammy." At this period comes in the third 
peculiarity of European calfskin tanning, namely : The 
skins are worked over a small half round beam, on the flesh 
side, with an ordinary tanners' worker. The object of this 
working is to complete and make permanent the work of 
breaking the nerve commenced in the beam house, and to 
take off any flesh which may remain. Its effect is to make 
the skin soft and the fiber elastic, and, being quite inexpen- 
sive, should never be omitted. It can be done by any ordi- 
nary yard hand who is faithful and honest, but there must 
be no slighting. 

One of the characteristics of foreign workmen is that they 
are faithful to instructions ; any manipulation which requires 
patient labor may be intrusted to them without fear of omis- 
sion or neglect. So much cannot be said for American 
workmen, particularly those who work by the piece ; they 
are constantly studying how to save labor, and the tanning 
and finishing of calfskins in a style as perfect as are the 
goods of our European neighbors consists of so many little 
things — all demanding careful, painstaking labor — that, 
without the greatest oversight on the part of the foreman, it 
is not to be expected that any large proportion of really good 
skins, such as the French and Germans make, will be manu- 
factured in this country for many years to come. 

After the skins have been tanned and " mooned," as al- 
ready indicated, they may be flesh shaved, as before de- 
scribed, or, as some prefer, they may be thrown into the 
wheel and "rough stuffed" before being shaved. The latter 
method is regarded as wasteful, since the shavings absorb 
oil, and to this extent cause a l n ss ; but many finishers claim 
that a better flesh is obtained when the skins are " rough 



THE LEATHER MANUFACTURE. 203 

stuffed" before the shaving is clone. The writer prefers the 
former course. 

In beginning the finishing process — the tanning and beam 
working on the flesh having been faithfully done— there will 
be very little or no loose flesh to shave off, and, while a 
"smooth face" must be obtained, it is desirable thai no 
more than merely the flesh should be removed with the 
knife at this period. From one to three pounds per d< 
may easily be lost by want of care at this stage of the pro- 
cess; therefore this shaving should never be done by the 
piece, but always by the day, and with the most conscienl ious 
workmen, for labor that is worth fifty cents per dozen can be 
made to cost the tanner two or three dollars by the loss in 
weight which the workman may cause. If, from any omis- 
sion, an unusual amount of old grain has been allowed to 
come into the grain of the skins, it may be advisable to board 
them to draw out such surplus grain, or rather to scatter it, 
while in this rough state, but this necessity will seldom arise 
if proper attention is paid in the tanning process. 

Assuming that all leather finishers have both scouring and 
stuffing wheels, it is recommended that, before scouring by 
hand, the skins be thrown into the scouring wheel, and all 
the bloom and dirt washed out. When this sen Lee is thor- 
oughly performed, the hand labor necessary is little more 
than that of striking out the sinn on both lies], and grain 

sides. 

As one of the characteristics of French finishing is to lea 1 
all the "stretch" in the skins rather than to take it out, we 
begin our new method by omitting almosi entirely the cus- 
tomary scouring and distending process. If the skin- have 
been well "struck" on both grain, and flesh, very much of 
the old liquor and water 1ms been pressed oul of them, bul 
yet they are too wet— the fiber is too full of water to allow 



204 THE LEATHER MANUFACTURE. 

the oil and tallow to properly enter, hence they should be 
partially sammied. This requires care, otherwise the oil will 
enter unevenly and darken the grain. 

Some curriers have hand presses, and hydraulic power 
presses are used, under which the skins are placed to force 
out more water than it was possible to press out with the 
slicker, but the observation of the writer is to the effect that 
exposure to the atmosphere is the only proper way of pre- 
paring the skins for the stuffing wheel, and after they have 
been thus exposed to the air a sufficient time to fairly stiffen 
they should be taken down and placed in piles, as in this sit- 
uation the moisture will distribute itself, drawing from the 
center to the circumference. 

Unless great care is observed stuffing leather by the use of 
the stuffing wheel may do incalculable damage. French in 
its origin — its present efficiency is wholly due to American 
adaptation. The oil and tallow should be held in separate 
vessels, warmed with a steam coil at the bottom of each, and 
thoroughly mixed while in this warm state. When the skins 
are properly sammied they should be thrown into the stuf- 
fing wheel, the proper amount of stuffing added, and the wheel 
set in motion. Ten to twenty minutes will suffice to mill this 
mixture of oil and tallow into the skins, but the wheel should 
be allowed to run long after the stuffing is outwardly ab- 
sorbed, since this fulling process will work the stuffing into 
the center and thicker portions of the skins. It is possible 
to put in an excess of oil and tallow, and this is quite 
common, but such excess may be got rid of in one of two 
ways, as follows: First, carefully pile the skins on each 
other as they come out of the wheel, and by their own weight 
the excess of oil will be pressed out; or, second, throw each 
skin on a table and gently work out the excess by means of a 
steel slicker, using judgment to press equally over the wholly 



r 



THE LEATHER MANUFACTURE. 

grain surface. If done with sufficient care, this action will 
relieve the flanks, pates and bellies of any undue pr porl 
of grease, and the skins ma}- then be hung up to dry, either 
from tenter hooks or over sticks. 

Although skins freed from the acid of the bark and satur- 
ated with oil are not so liable to be affected in their color by 
means of light and air as ordinary tannages, yet they are 
sufficiently so to require care in these respects. The drying 
loft should, therefore, be so constructed as to enable the at- 
tendant at all times to regulate the amount of light and air 
which should enter, and the drying should be slow. It will 
always be safe to allow night air, which is without light, to 
enter. In the winter months great care should be taken to 
avoid excessive stove or even steam heat, the tendency of all 
artificial heat being to make the leather harsh and bring the 
grease to the surface. 

After the skins have been stuffed and dried in the mam in' 
indicated they may be packed away in piles of 200 or 300, 
and allowed to remain for a great length of time, as they will 
improve all the while. It is in this condition thai the 1 
stocks of Europe are carried, goods made out<>. asou o 
which are unsalable from any cause being thus held over 
years. ' 

The process of slicker whitening is preferred to tin 
method for three excellent reasons : 1. Less of the • 
is taken off. 2. A better (smoother! face is Li it. ::. A wort 
man can do more work with one of these fco '1- than with Hie 
usual whitening knife. 

While the skin is in the dampened con ! i ion, which has 
been brought about both for the convenience and more 
effective work of the slicker whitener, it is thrown upon i 
table covered with leather, grain up, and by means of a 1 
"grain boarder," held firmly by the whole aim, tin 



206 THE LEATHER MANUFACTURE. 

skin passes under the operation of the board, but especial 
attention should be paid to the neck and pate, or wherever 
else an old, elongated grain may be seen. The effect of the 
boarding will not be to make the grain entirely smooth, but 
so to scatter it as to render it less observable. It is no part 
of the duty of the French currier to make a smooth grain ; 
indeed, this is just what he wishes to avoid ; but it is part of 
his art to make a smooth and fine flesh surface with a grain 
so loose and yielding as to adjust itself readily to the opera- 
tion of the crimper. 

Contrary to our manner of proceeding, the calf and kip 
skins in Europe intended for boots are not blacked on the 
flesh until after the} 7 are crimped on the boot trees. They 
are bought, sold and held in the " russet " state. While in 
this coDdition, (cut in forms), they are carefully inspected, 
and wherever small cuts, hacks or flaws of any kind are ob- 
served on the flesh they are buffed or shaved out. The effect 
of this operation is to make the skin slightly thinner at the 
defective point, but in cutting in forms these defective spots 
are so located as not to injure the wear, and at the same time 
to escape the notice of the consumer. This work is done by 
boys or women, who, with broken glass or thin turned steel 
edges, pare down the lips of the cuts or hacks so caref ully as 
to hide them from view. After this is done, the fronts are 
blacked, if a special trade demands it, but usually the goods 
pass to the manufacturer in the russet state, to be by him 
blacked after they are made up. 

Before crimping the boot front, the grain at the instep is 
buffed from each front. The reasons for this are as follows • 
1st. If the grain is left on the crimp would pucker it, and 
render it rough to that portion of the foot ; 2d. By removing 
the grain the crimp is effected with less labor, as that portion 
of the skin is made more elastic ; 3d. The tendency of the 



THE LEATHER MANUFACTURE. 2l>7 

process is to force more volume of fiber just at the turn than 
elsewhere; but 4th, and mainly, it softens the skin at tin- 
point where there is the greatest friction and pressure on the 
muscles of the foot. It is quite notorious that buffed leather 
is much softer than that in which the grain is left on, and it 
often happens that men with tender feet require their calf- 
skins to be buffed over the whole grain surface before being 
made up. The reasons for the practice of buffing so much 
of the crimped form as covers the instep will therefore ap- 
pear sensible. 

The leather finishers everywhere south of Great Britain 
use very largely and quite uniformly the vegetable oils, 
mixed with tallow, instead of the fish oils used by us. This 
difference alone is quite enough to account for much of that 
softness and elasticity of fiber so much admired in their 
leather product. The degras of France is about the equiva- 
lent of the sod oil of Great Britain and the buckskin oil of 
America, but there is this difference between them : V< tgi - 
table oils make the base of the degras while fish oils make 
the base of buckskin and sod oils. Palm oil is very largely 
used by the calfskin manufacturers of France and Switzer- 
land; cocoanut oil, castor oil, cotton seed oil, and, by parity 
of reasoning, linseed oil, may all be serviceable, but fish oils 
should never be used. They cause leather to gum, and their 
whole nature seems destructive to the fiber. 

There are three general defects which should not be over- 
looked in the French methods of manufacture : 

First — They do not properly trim flair skins: the offal 
usually found on French calfskins is so thick and co tree as 
to be perfectly worthless. That a people otherwise so eco- 
nomical in their methods should have fallen into this defective 
manner of trimming, if, indeed, it can be called trimming al 
all, and continue the practice for so man\ years, is a matter 



208 THE LEATHER MANUFACTURE. 

of surprise to all thoughtful persons who have to do with 
the manufacture. 

Second — By the French method of tanning and finishing 
the leather made is less impervious to water than that made 
by either the English or American methods, rendering the 
former only suited to dry climates, or for wear in large cities, 
where it is not exposed to wet or damp soils. 

Third — The starved nature of their tannage — the very 
effort they make to render their leather soft and yielding in 
texture — deprives the shoulders, bellies and flanks of that 
gelatine which, when combined with tannin, enables the 
manufacturer to cut his stock to the very outer edge, thus 
making every square inch serviceable. 

It is in great measure from the want of fineness in the 
offal of foreign goods that our shoe manufacturers are sub- 
stituting American for French calf. So long as our people 
wore boots the coarse offal of the French stock could be run 
up into the legs, but now that we have become a nation of 
shoe rather than boot wearers, the change has induced a re- 
versal in the public judgment in regard to the economy of 
the French method of tanning and finishing calf. 

Perhaps also it is due to the American calfskin manufac- 
turer to concede that he has greatly improved in making a 
more elastic fiber, while he has retained the fineness of the 
offal and closeness of trim. It must be within the observa- 
tion of all leather consumers in this country that both calf 
and wax upper leather have undergone a great change for 
the better within the past few years. A few more s-trkh'X 
forward and the upper leather of America will stand on a par 
with that of the best productions of the most advanced 
nations of Europe. 

In respect to the proper classification of skins the French 
and German tanners have always had the advantage, and 



THE LEATHER MANUFACTURE. 209 

this is especially the case with those large manufacturers 
sending their stock to this country, who produce as many as 
from 2,000 to 3,000 dozen per year, and in exceptional ca 
vastly more. This enables them to select male from fern 
skins, and make several qualities and selections inside these 
general classes. Until the calfskin tanners of America shall 
imitate the French tanners in this particular they will labo 
under present disabilities, but the energy and forethought 
which has brought us so near competing on equal term-, 
will, there can be little doubt, carry us through to thai 
desired period in our international intercourse when our 
tanners shall no longer fear the effects of the removal of all 
duties, and a free exchange in all the leather products, to the 
mutual advantage of all the nationalities of the world. 



14 



CHAPTEE XXIII. 
GRAIN AND BUFF LEATHER. 

SPLITTING MACHINES MAKING SPLIT LEATHERS FROM GREEN HIDES OR 

FROM TANNED LEATHER EVERY KIND OF NATURAL GRAIN SUCCESS- 
FULLY IMITATED STRENGTH AND DURABILITY OF SPLIT LEATHERS 

THEIR INTRODUCTION TO EUROPEAN CONSUMERS ESSENTIALS TO BE 

CONSIDERED IN THE MANUFACTURE OF GRAIN AND BUFF LEATHER. 

Commencing with the successful introduction of the union 
splitting machine, about the year 1830, leather made from 
the hides of neat cattle has been split down to a compara- 
tively thin substance, and the "grain splits" have been used 
extensively for shoes, as well as trunks, harness, etc. With 
the improvements made in that machine in later years, very 
safe and good work has been done in splitting the ordinary 
cow hides into both stout and light graiu leather, while the 
best of the flesh splits has been used extensively for boot 
1 >acks and shoe quarters, and the middle splits for trunks. 
More recently, or about 1860, the " endless belt knife split- 
ting machine " came into use, and it splits with even greater 
precision than the union machine. From its high cost 
(about $1,000), as well as from its complicated structure, 
making it liable to get out of order, comparatively few of 
these machines are in use. When it is new and in good 
order, and handled by a competent workman, an ordinary 
cow hide can, with it, be split into three, and even four dis- 
tinct parts, with as great precision as the sheepskins of 



THE LEATHEE MANUFACTUEE. 'J 1 1 

England are split grain from flesh. The merit claim 1 
this endless belt machine is that the fiber of the hid 
without strain, while it is alleged that with the union ma- 
chine considerable force is required to draw the side through. 
This objection had much force with such machines as were 
constructed early in the history of splitting leather, but with 
the improvements since introduced, there is no perceptible 
disturbance of the fiber, and no greater power is requi i 
than can be applied with the attendant's hands. These 
union machines are now so perfect and durable in their con- 
struction that they may be said to be indestructible by ordi- 
nary wear, and, with average skill and care, grain leather of 
the thinnest description can be split from the ordinary neat 
hide. An illustration of the union leather splitter will be 
found in subsequent pages. 

So much has been said in regard to the machines and 
facilities for splitiug that we may consider the in 
merits of the grain and buff leather which has for the | > 
years come into such universal use in this country, and is 
now, by its cheap and excellent qualities, commending itself 
to all the countries of Europe. A clear distinction must 
kept up between the process of manufacturing '!■ 
and buff leathers from the green hide and those made from 
tanned leather. Our curriers are too often tempted t<> split 
down fully tanned leather into grain. Such < • II*. >rts brh 
disfavor all grain leather, since, from the very nature of the 
case, the grain must be tender when fully tanned In 
split afterward. It is a great misfortune thai grain leather 
made in this improper manner cannot be discrimina 
against by buyers, as it is almost sure to give di 
when made up into shoes; but, tempted by fl c 
or two cents per foot, manufacturers are too apt to " ti 
this one lot," and that one lot, however small, carries die 



212 THE LEATHER MANUFACTURE. 

credit to a whole class of goods. These objections apply 
only to light women's grain. Men's boot gvain, which is 
split to weigh seven to eight ounces to the foot, will have 
substance enough to hold against any strain. 

But the object of this chapter is to consider the intrinsic 
qualities of modern grain leather, manufactured in imitation 
of calf, goat, seal and even hogskins. By far the largest por- 
tion is manufactured as "pebble" or "goat." The 'grain is 
made coarse or fine, to suit the taste of the purchaser. In- 
deed, with present appliances, an order can be filled at short 
notice with just such devices imprinted on the grain as may 
be desired, and without additional cost to the purchaser. 
Probably there is no animal that lives whose skin cannot be 
imitated, so far as the external appearance is concerned, and 
this can be done by a machine which will duplicate the im- 
pression indefinitely. The effect of the production of this 
description of goods on the manufacture of goatskin morocco 
in Europe is just beginning to be felt. In this country its 
influence has been very perceptible for the past five years. 

The question which consumers desire to be satisfied upon 
is as to whether it is tough, so that it will wear without tear- 
ing or cracking. In respect to " cracking " there can be no 
hesitation in saying that, from the nature of the pelt and its 
treatment, it is not more liable to crack than East India kips, 
goat or seal skins. It will also take as durable a color, i. e., 
it will not turn " foxy." But is it as lasting in general struc- 
ture ? Can a part of a pelt be made as strong as the whole ? 
The answer is both no and yes. In the bending of the fiber 
of the leather so frequently as is made necessary on a man's 
or woman's shoe, the stock is a great deal more liable to 
crack if it be of thick leather than if thin, but if the thin 
leather is made from a pelt that has its whole structure, both 
flesh and grain, and all intermediate fiber, it must be more 



THE LEATHER MANUFACTURE. 

serviceable than when this structure is broken, as is the c 
with these split grain leathers. But suppose we admit th 
this grain upper is Jess tough than goat, seal or hors • 
leather, if it is sufficiently tough to wear out two pairs of soli s, 
as is affirmed by our experience, and can be offered at thirty 
per cent, less price than all competing leather, then will it 
not be pronounced a success, and will it not largely take the 
place of these leathers throughout Europe ? That it will 
greatly affect the consumption and price of goat, calf, s 
and horse leather throughout the whole world there can be 
no doubt ; whether it shall ultimately come into general use 
for women's and children's shoes will depend upon the hon- 
esty and fidelity with which it is manufactured. It is now 
almost exclusively made in this country, and because we 
have the machines to split successfully the hides. When 
the leather manufacturers of Germany, Austria, Switzerland, 
and even France, shall turn their attention to the production 
of this leather they will successfully compete. Outside of 
our machines and our trained hands for splitting we have no 
advantages over those countries. Indeed, their cowhides 
are finer in grain than ours, and as their neat cattle are 
almost exclusively cows, there can be no reason to question 
a full supply of the raw material. The improved breeds of 
cattle in Great Britain will also give the English tanner i 
most suitable cow hide for grain upper. 

The question, then, of substituting split grain for the slrii B 
of the smaller animals is one as broad as the two Continen 
In view, therefore, of the largeness of the subject, lei us con- 
sider in conclusion some of the methods and economies of 
manufacturing this grain and buff leather for women 
children's shoes. 

First— The hides must be free from all scratches, and 
horn and hook marks on the grain. Cows sent from the W< 



214 THE LEATHER MANUFACTURE. 

on cars will not produce hides sufficiently free frain the above 
defects to make grain leather. 

Second. — The hide should not weigh over 40 to 45 pounds, 
cured and trimmed weight. Leather made from old and 
heavy cow hides the grain is coarse, and when cut down thin 
is tender. 

Third. — They should be worked in when as fresh as pos- 
sible ; hides that have laid in the salt for a long time are apt 
to have a " frized " grain. 

Fourth. — The lime should be worked out thoroughly ; warm 
water in the wheel will do this to a limited extent, but bates 
should be used as a last resort before final working. 

Fifth. — Our best grain leather manufacturers handle and 
even tan by suspending the sides ; this practice makes the 
shoulders and flanks vtry fine. Whether it adds to the 
toughness of the grain may be questioned ; but for buff 
leather it is indispensable, and even for grain it presents so 
many advantages that it may be doubted whether any man- 
ufacturer can afford to dispense with the practice. 

Sixth. — The side is colored and raised before splitting ; that 
is, the sides are handled on sticks (suspended) until they be- 
gin to feel firm and put on the appearance of leather. This 
usually occupies ten days in a weak liquor, when the sides 
are taken out, drained and stiffened, (by being hung up in 
the loft). They are then split. Usually there are two splits 
taken off, one main split, and one junior or small one, which 
covers the kidnevs, but which does little more than flatten 
the side. If these freshty split parts are thrown back into a 
strong liquor, or even one of moderate strength, without 
wheeling or brushing, they will become "crusted" over, 
and will not take the tan ; but if thrown into the wheel for 
a few moments, and run in a weak sour liquor, then all dif- 
ficulty on this score is avoided. The old method of brush- 



THE LEATHEi: MANUFACTURE. 215 

ivg with a stiff brush is now considered too expensive, par- 
ticularly as the wheel answers the purpose. After this 
wheeling the grain portion is hung in the vat and the split 
portion is laid away with bark. 

Seventh. — The liquor in the vats is changed, but not the 
sides. Some run off, say one-quarter or one-third of tin * 
liquor into the junk, and pump back on the newer packs, re- 
plenishing the head packs with new liquor from the lead 
while others press round, their yards on the same principle 
that the press leaches are run. In either case great care 
taken to feed the leather both slowly and uniformly, so that 
the grain is kept soft and full without "drawing." The 
effect of this method is to give to the grain portion of the hide 
the same amount of tanning that would be given to a whole 
skin, i. e., it is tanned from both sides, leaving in the center 
an imaginary line of partially tanned or only colored fiber. 
This imparts a toughness that distinguishes the leather from 
ordinary grain leather made from fully tanned hides. 1 \y 
reason of the thinness of the grain portion very weak liquors 
can be used, and yet the tanning is completed in thirty or 
forty days. It may seem anomalous, but it is ncvertln I 
true, that tanning makes the fiber of hides comparatively 
tender, or less tough, and, beyond tanning sufficiently to pre- 
serve the gelatine, the further filling of the fiber for uppei 
leather should be avoided. The weak liquor process, thru. 
which these grain leather manufacturers are enabled to pur- 
sue, is well calculated to make a tough fiber. 

Eighth. — Another advantageous resu II of splittingthe hides 
intended for grain leather while green is that we gel rid ol 
the less elastic fiber of the flesh, including the aerve, and the 
grain will stretch until it comes to its proper bearings. This 
nautical expression conveys the idea perfectly. The fibei 
must be distended before it goes into the shoe, and it is betto I 



216 THE LEATHER MANUFACTURE. 

to let it distend itself while green than to tan it and stretch 
j* afterward. This point may seem obscure and even doubt- 
ful, but the writer is satisfied that there is much in it. To 
illustrate — "Why is it that damp or wet leather is much 
tougher — will bear greater strain — than that which is dry? 
Simply because all the fiber pulls evenly when wet, but when 
dry there is not the same uniformity. For the same reason, 
a side of rough leather is less tough than the same side after 
being scoured and set out, and when grease is added still 
greater strength of fiber is secured. It is found that, in the 
manufacture of wire rope, greater strength is secured by lay- 
ing the wires side by side in a bundle, rather than by twisting 
them lip as in a rope. Now it may be assumed that the more 
equally and perfectly the fiber of the hide can be distended 
the greater will be the aggregate strength. "Whatever may 
be the rationale of this subject, the fact stands conceded that 
grain leather manufactured in the way indicated is much 
touglier than when made in the old way. 

The scouring, stuffing, blacking and embossing, is con- 
ducted much in the same way as by the old method. Each 
of these processes are greatly facilitated, however, by having 
a uniform substance and tannage to treat. The bloom and 
extractive matter, for instance, can be washed out of these 
grain sides in the wheel so completely that they require little 
more than smoothing off before hanging them up to partially 
dry before stuffing. 

In all trades a better result is obtained when a proper 
division of labor is observed, and this is notably true in the 
manufacture of this description of leather. We have now 
several large manufactories devoted exclusively to the pro- 
duction of grain and buff leather. They keep in mind the 
result they wish to produce from the beginning, and only 
buy such hides as will suit their purpose. This regard to 



THE LEATHER MANUFACTURE. 217 

true economy is not new in Great Britain or France, lm; 
here, although, the indications are not few that our tanners 
are waking up to a better conception of the true economi> - 
of their profession. With this changing condition of the 
trade, it may be possible that the morocco and calfskin tan- 
ners of our country have greater occasion to fear competition 
from our home "pebble grain" manufacturers than from 
foreign importations of their own goods. 



OHAPTEE XXIV. 
CUEEYING AND FINISHING. 

THE STUFFING WHEEL AND HOW TO USE IT — TO PURIFY AND CLEANSE DIRTY 

GREASE HOW TO MARE STUFFING- — FLESH BLACEING FLOUR AND 

SIZE PASTES HARM THAT MAY BE DONE BY DEPENDENCE UPON RECIPES 

DAMPENING LEATHER BEFORE AND AFTER APPLYING OIL AND TALLOW. 

Iii a conversation with Mr. Charles Korn, (than whom no 
man in America is better informed on the philosophy and 
practical methods of dressing and farming leather), the writer 
asked him to commit to writing his views on the general sub- 
ject of his profession. He said: "Impossible! It would 
only mislead ; no man can know how to finish leather from 
any written statement, however clearly expressed." To the 
request to write out for publication his methods of making 
oil and soap blacking ; also his methods of compounding >ize 
and paste, clearing oil that is impure, etc., his general answer 
was that it was not practicable. Nothing short of practical 
experience, adapting each mixture to the particular kind of 
leather had in hand, would ever make a successful and work- 
manlike job. And he was right. As well might a landscape 
or portrait painter attempt to give directions how to paint, 
as for a currier to attempt to give written instructions how 
to finish leather. 

There was one subject that Mr. Korn did discuss with 
considerable warmth. Several efforts having been made to 
patent the stuffing wheel, which he introduced and gave to 
the trade, without claiming a patent, he said that all attempts 
to heat up the air, or the oil and tallow, by inserting coils of 



THE LEATHEE MANUFACTURE. 219 



steam pipe inside of the wheel, or by introducing heat arti- 
ficially in any way, were useless. His method of mixing his 
oil and tallow had been uniform and always successful. The 
oil and tallow should be heated separately and mixed, before 
putting into the wheel, in such proportions as the nature of 
the leather and the season of the year require ; in the win- 
ter months less tallow and more oil ; in the warm, sum: 
months, more tallow and less oil — both seasons varying 
an equal quantity of each, according to the circumsfcanc 
It is desirable to get as much tallow in the leather as possi- 
ble, without making it hard or causing it to " spew." If the 
oil and tallow congeal and attach to the sides and corners 
of the wheel, as is often the case, a jet of steam from a pipe 
applied to the inside of the wheel for a few minutes will so 
soften it as to make it limpid, when it will unite with the 
fresh oil and tallow. When once the wheel is in motion, the 
friction occasioned by the rubbing of the sides or skins 
against each other will produce heat enough to keep the oil 
and tallow from congealing, particularly if the atmosphere is 
moderately warm in the shop, as it should be always. 

It is a remarkable fact that, long after this wheel was 
introduced into public use here, a Scotchman visiting his 
native country, and seeing that his people had not heard • 
this improvement, actually sold the exclusive righl to use the 
machine to a very large and enterprising mamifactui ing firm 
in Leeds. With the free intercourse between the leather 
trades of Great Britain and the United States al this time 
it would hardly be possible to repeat that operation. 

The slicker whitener, which has now come into almost nni 
versal use, is to be superseded, as many think, for all v. 
except calfskins, by one of the three newly patented whitei 
ing machines noticed in subsequent pages. 

The purifying and cleansing of dirty grease before it is 



220 THE LEATHER MANUFACTURE. 

put on the leather is accomplished by applying heat. Usu- 
ally, the sun on a warm clay will clarify oil that is exposed to 
its rays. But the more speedy and effective way is to place 
the dirty grease in a barrel, and, for every thirty gallons, 
apply about one quart of sulphuric acid ; stir it very thor- 
oughly, and afterward steam the oil until the whole fairly 
boils. The condensed water from the steam, aided by the 
acid, will disengage all or most of the impurities of the oil, 
and carry them to the bottom, when the whole is allowed to 
stand and settle. The dirt may be drawn by a faucet from 
the bottom, or the oil may be carefully dipped off from the 
top. In this way the writer has seen railroad grease, as 
black as ink, so purified as to make very serviceable oil. 
This railroad oil is obtained from the cotton waste used in 
the boxes of the axles, and is probably the most unsightly 
oil offered the currier, and yet it can be made serviceable in 
the way indicated, both as to cleanliness and color. If the 
acid should prove objectionable then pulverized chalk, stirred 
in the oil and allowed to settle, will carry down and off its 
objectionable features. The currier will seldom have oil as 
bad as this to handle ; generally he has only the common 
"head fats" and scrapings from the tables, which will yield 
to the treatment above indicated most readily. 

A small tank or hogshead may be kept standing in a con- 
venient place, with one head out, and fitted with steam coil 
in the bottom ; it should have, also, two or three faucets at 
short distances apart, near the bottom, from which all impu- 
rities may be drawn ; this apparatus will prove a most use- 
ful one in the purification of all greases. If steam is not 
condensed in the oil, but the heating is done by a close coil, 
then water should be freely poured in with the oil, and all 
boiled together. 

The making of stuffing with ordinary oil and tallow is well 



THE LEATHER MANUFACTURE. 25 ! 

understood, but of the use of degras or sod oil in conn 
with oil and tallow less is generally known. Mr. Korn I 
nishes the following suggestions : Melt the tallow, and 
it stand until it is partially cool. If, however, degras or s< i 1 
oil be mixed with the tallow, it must be stirred in while I 
tallow is hot ; the oil added may be put in while the tallow is 
cooling. A little- water with the sod oil and degras will 
lighten the color very much, but the oil must be added af 
never before the degras. 

Flesh blacking is made either with lampblack and soap or 
lampblack and oil ; if " soap blacking" is used, oil is freely 
applied afterwards to fasten the color and body of the black. 
The principle advantage claimed for soap blacking is that it 
fills the flesh with a better body and covers defects wl i 
show through if oil and lampblack alone are used. The dis- 
advantages are that when this leather is crimped for bo 
the blacking washes off and leaves a coarse surface, while the 
alkali in the soap will, if allowed to lie for a long time, in 
or less destroy the grease and impart a harsh feeling to 
leather; pure oil blacking will grow softer by age. Far 

as known to the writer soap blacking is now used in no otl 
country, and is at present used here only hi the modif 
form to which attention has been called. 

Flour paste is used first after the soap black ing. It is made 
of flour, with soap added — say to every pail of flour use two 
pounds of hard brown soap, which is to be boiled with 
paste. Some add tallow also — for every pail of flour pa 
using a piece as large as an egg. 

Size paste is made as follows: Dissolve four ounce 
glue in warm water ; add a small piece of fcallow, say half an 
ounce; dilute in water until the proper consistency is ob- 
tained to spread easily with a s] 

The writer refrains from giving further suggestion »on1 



222 THE LEATHER MANUFACTURE. 

topics lest he should subject himself to the criticism with 
which Mr. Korn closed his observations : " Writers of books 
and lecturers are mere theorists, and are seldom good work- 
men." A small treatise on Tamiing and Currying, by " a 
Maryland tanner and currier," in addition to other leading 
suggestions, contains " twenty-five valuable recipes," on which 
hang most of the principles involved in the tanning and fin- 
ishing of leather. Should the writer attempt to imitate his 
example, and lay down the absolute rules of action govern- 
ing all cases, giving recipes in a dogmatic way, it would 
probably do more harm than good. For instance urine, 
until within the past twenty years, has been the only known 
solution to kill the grease preparatory to the blacking of the 
grain of leather, and all recipes were based on this chemical 
agent. Now, the chemist who suggested that any other 
alkali would do this service just as well and a great deal 
more uniformly saved the currier one of his greatest nui- 
sances, and insured a much improved result. At present the 
use of soda ash or sal soda takes the place of the "sig." 
barrel. The recipes above mentioned are full of antiquated 
notions of this kind, which it will be well to forget as soon 
as possible. What we want to know is the chemical charac- 
teristics of all the agents we employ. Then we shall know 
how to substitute the one for the other, and learn to employ 
those that are the most economical as well as serviceable. 

In closing this chapter the writer would call attention to a 
new and, to some extent, revolutionary idea in regard to the 
stuffing of leather. It has always been held indespensable 
that leather should be partially wet or dampened before the 
oil and tallow was allowed to enter the fiber. If applied 
when too wet the oil would not enter, and if too dry the fiber 
would be "burned ;" this has always been the popular idea. 
No miner would think of oiling his old boots, no farmer his 



THE LEATHER MANUFACTURE. 22:'. 

old harness, no mill owner Ms old belt, without soaking in 
water and preparing the leather to receive the grease. 1 
the opinion of the writer that no greater fallacy ever pre- 
vailed. Worn out leather — that is, leather that has lost its 
vitality by the evaporation of its grease, should be replen- 
ished by having grease applied to it while in a dry stale, and 
after the oil or grease has entered and been absorbed by the 
thirsty pores, then should follow warm water to modify and 
control the action of the oil. It will be seen at once that the 
oil has taken its place in the center of the leather, while the 
water is on the outside and maybe evaporated easily; but 
if the water is inside it has to pass the oil, and there must 
be delay. If the oil is lodged in the center it must work 
toward the surface very slowly, and when evaporated, which 
will require months and even years, then it must be replen- 
ished in the same way. 

It may be asked why soak with warm water at all, on tin's 
theory? Why not soak with oil and tallow exclusively? The 
answer is because the oil, under such circumstances, will 
"slough" off, but if water not exceeding 110 degrees in heal 
be applied it will drive in the oil from the surface and modify 
that greasy feeling and untidy appearance which attaches 
over stuffed leather. Over stuffed leather can also be cured 
of its defects by being immersed in hot water to the extend 
above indicated. If no thermometer is at hand to fcesl the 
degree of heat it will be safe to immerse the ever stui 
leather for one minute in water as warm as the human hand 
and pulse can bear, and the result will be thai all the exc 
of grease will be driven to the center, and the surface will 
dry fair. That no oil has passed out of the side v. ill be 
demonstrated by the fact that no grease will appear on the 
surface of the water. It must then have gone in, whicl 
be shown by the retained weight. 



CHAPTER XXV. 

DIRECTIONS FOR THE CONSTRUCTION OF DETACHED 

FURNACES FOR BURNING WET SPENT TAN. 



BY THERON SKEEL, C. E. 



The problem in designing a furnace and boilers for burning 
wet spent tan to furnish steam for a tannery is different from 
that in designing a furnace for coal or wood in that the fuel 
has generally no value for any other purpose, all that is not 
burned being thrown away. In case the tannery is not 
located where the spent tan can be run off through the 
bottom of the leach by a stream of water, but where it has 
to be shoveled from the leach and carted away, tanners 
will find it cheaper (so far as first cost) to burn all the tan 
they leach, for by so doing the boilers may be made smaller 
than would be necessary if they burned as little tan as they 
could get along with, but as the heat is more intense they 
will burn out sooner. A sole leather tannery can be run by 
burning about one-half the tan leached, if the ovens and 
boilers are well proportioned, while an upper leather tannery 
will need to burn nearly all the tan leached, even in the best 
form of furnaces and boilers ; or, if the furnaces and boilers 
are of inferior design, will run short of bark at certain seasons 
of the year. 

A tannery producing annually 20,000 sides of sole leather 



THE LEATHEE MANUFACTURE. 

will need for tanning about 2,000 cords of hemlock bark, 
measured before being ground, and must burn one-half of 
this, or 1,000 cords, to make all the steam used in the tannery 
to run engines and pumps, heat liquor, etc. The weight of 
an average cord of air-dried hemlock bark, as measured in 
the pile before being ground, will be 2,000 pounds. In the 
process of leaching this cord of bark will lose nearly 400 
pounds, and the portion remaining will weigh 1,600 pounds 
in the same state of dryness as before being leached, but as 
it comes from the leaches will bring with it in addition 2,000 
pounds of water, making the weight of the wet spent tan re- 
sulting from one cord of chip bark 3,600 pounds. The total 
weight of spent tan, therefore, produced each year by a 
20,000 -side sole leather tannery will be (3,600X2,000=1 
7,200,000 pounds, and the weight of the portion that must 
be burned, being about one-half — 3,600,0C0 pounds. 

If the machinery of the tannery runs twelve hours a day 
and -00 days in the year, the total number of hours will be 
(300X12=) 3,600, and therefore the weight of wet spent tan 
that must be burned each hour in a furnace and boilers of the 
best construction and design (3,600,000^3,000=) 1,000, or a 
thousand pounds an hour, 

Table I is computed in this way. 

Table I. — Weight oe wet spent tan that must be burned bai b hour 

IN A FURNACE AND BOILER OF BEST CONSTRUCTION TO FURNISH \M. 
THE STEAM NECESSARY FOR THE TANNERY, II' 'i':ii SIAOHTNER1 ' 
12 HOURS A DAY AND 300 DAYS A YEAR. 

Number of Sides Poun l&of W | - 

• Tanned Annually. Burned En h Boor. 

10,000 500 

20,000 1,000 

50,000 2,500 

80,000 t,000 

100,000 5,000 

15 



220 THE LEATHEE MANUFACTURE. 

Having determined how much tan must be burned, the next 
consideration is whether the oven shall be fed from the top 
or from the front. Except under very exceptional circum- 
stances I consider it is better to feed from the top. If the 
oven is fed from the front one man cannot feed fast enough 
to keep up steam in a larger tannery than 60,000 sides, even 
if the tan is brought into the fire room floor by a laborer, 
(if he has to attend to the water in the boiler at the same 
time,) while, if the oven is fed from the top, one man can 
supply bark fast enough to keep up steam in a 200,000-side 
tannery. An oven fed from the top does not need nearly 
such close attention as an oven fed from the front. The 
former may be filled up and not touched again for an hour, 
if the fireman's attention is withdrawn, as often happens 
when the pump breaks down or in other cases, while the 
oven fed from the front must be supplied with bark every 
fifteen minutes. An oven fed from the top may be smaller 
than is admissible in an oven fed from the front, and requires 
less skill in firing. The only case when it would se'-m desira- 
ble to use an oven fed from the front is when it is very incon- 
venient to get the bark up on top of the oven, or when there is 
a small night over the oven, as when the floor of the room 
.ve is so near the top of the oven as to be in danger from 
fixe.. 

In order to successfully bum wet tan it is necessary that 
the surface of heated brick work surrounding the tan in the 
furnace should be large in proportion to the weight of tan 
burned, in order that this surface should not be cooled off by 
the water evaporated from the fresh charge of wet tan, below 
the temperature necessary to ignite the gases given off by 
that tan after it is dried and before it commences to burn. 
This condition requires a large oven and a slow rate of com- 
bustion, .It is found in practice that the combustion is sen- 



THE LEATHER MANUFACTURE. 227 

sibly perfect when the wet spent tan is burned at the rate of 
15 pounds on each square foot of grate surface per hour. 

Table II is calculated from Table I in this way, and gives 
the necessary grate surface for a furnace feci from the top. 

Table II.— Area op grate surface necessary in a tannery burn- 
ing ONE-HALE THE TAN LEACHED IN AN OVEN FED FROM THE TOP 
TO FURNISH ALL THE STEAM NEEDED, THE MACHINERY lttWXIN'n 12 
HOURS A DAY AND 300 DAYS LN THE YEAR. 

Number of Sides Area of Grate 

Tanned Annually. in Square Feet. 

10,000 33 

20,000 66 

50,000 166 

80,000 266 

100,000 333 

This amount of grate surface may be obtained in several 
ovens if necessary. The ovens had better be at least 6 feet 
wide, and as long as convenient. The feed holes should be 
two-thirds of the width of the oven between centers, that is. 
for an oven 6 feet wide the feed hole should be 4 feet bet ween 
centers. The feed holes may be 12 to 18 inches in diameter 
at the top, and larger at the bottom, as the bark is fed in 
more easily through a large hole than a small one. Tin 
hight of the oven, measured from the grate bars to the crown, 
should be three-quarters of its width, that is, an oven 6 feet 
wide should be 4| feet high from the crown to the grate. 

In order to take up sufficient heat the heating surf) in 

the boilers should be one-half of one square foot for each 
pound of wet spent tan burned per hour in an oven fed horn 
the top. This amount of heating surface will reduce the 
temperature of the gas in the chimney to aboui 600 . Table 
III is computed from this proportion. | The heating surface 
is all the surface of the boiler, whether on the sin II or in the 
flues or tubes, that has water on one side and the hoi gas oil 
the other.] 



228 THE LEATHER MANUFACTURE. 

Table III. — Area of heating surface necessary for a tannery 

HAVING AN OVEN FED FROM THE TOP, AND BURNING ONE-HALF OF 
THE TAN LEACHED TO MAKE ALL STEAM USED, IF THE MACHLNERY 
RUNS 12 HOURS A DAY AND 300 DAYS IN THE YEAR. 

Number of Sides Area of Heating Sur- 

Tanned Annually. face in Square Feet. 

10,000 250 

20,000 500 

50,000 1,250 

80,000 2,000 

100,000 2,500 

In case an oven fed from the front is used, the heating 
surface' must be 20 per cent, more — that is, for a 10,000-side 
tannery, 300 square feet, etc. 

In order to burn the wet spent tan at the rate given the 
chimney must be at least 70 feet high and must have an area 
of at least one-quarter of one square inch for each pound of 
wet spent tan burned per hour, but the performance will be 
more satisfactory if the chimney is made 100 feet high, and 
of an area of one-half of one square inch for each pound of 
wet spent tan burned per hour. The caller chimney will give 
a better draft, which will get up steam quicker after it has 
been allowed to run down, while the larger area will give a 
slower current in the chimney, and the sparks will not be so 
likely to be carried from the chimney and to endanger the 
agjacent buildings. The chimney may be made of sheet 
iron, but. brick is recommended as a better material, or sheet 
iron lined with brick. The iron, if not lined with brick, in 
time rusts out, and cold air leaks in and spoils the draft. 
The brick when once built is permanent. A larger chimney 
than given in the following table (calculated at the rate of 
one-half of one square inch to each pound of wet spent tan 
burned per hour) is an advantage. 



THE LEATHER MANUFACTURE. 229 

Table TV. — Dimension of chimney necessary to consume one-hali 

OF TAN LEACHED WITHOUT ENDANGERING SURROUNDING BUILDINGS I/. 
SPARKS CARRIED UP BY CURRENT OF GAS WHEN MACHIN I BUNS DUR- 

ING 12 HOURS A DAY FOR 300 DAYS IN THE YEAR. 

„ , „ „., . . „ Diameter of Chim- Sides of Chimney. 

Number of Sides Area m Square ney, if it is Circu- Lf it is square ' 

Tanned Annually. Inches. lar, in Inches. [nchea 

10,000 250 18 16 

20,000 500 25 23 

50,000 1,250 40 36 

80,000 2,000 50 45 

100,000 2,500 56 50 

The size of the chimney may be the same whether the 
oven is fed from the top or from the front. There must be 
a damper in the chimney, or what is better, a damper be- 
tween the outlet of each nest of boilers and the chimney, to 
regulate the draught. 

The cross section of the flues or tubes in the boiler must 
be (in the case of an oven fed from the top) as great as the 
necessary area of chimney, or one-quarter of a square inch 
for each pound of wet spent tan burned per hour, for the gas 
is hotter and more bulky when it enters the flues than when 
it enters the chimney. Only one pound of wet spent tan can 
be burned for each one-quarter square inch of area of the 
flues or tubes in an oven fed from the front, but the flues or 
tubes may be made larger than this, and the drafl checl 
bv the dampers or ash-pit doors. Thus, if a tanner has an 
oven fed from the front and two horizontal Hue boilers witti 
two twelve-inch flues each, the total cross section is 152 
square inches, and the greatest weighl of we\ spenl tan thai 
can be burned per hour is (452-f-^=) 1,808. Bui in ord< r to 
get perfect combustion the flues should be twice as large as 
this, or one-half square inch area for each pound of we\ spent 
tan burned per hour. It is of no advantage to have thefl 
or tubes of larger area than one-half of one square inch 



230 THE LEATHER MANUFACTURE. 

each pound of wet spent tan burned per hour, (as given in 
table V,) and all tubes or flues added after that area is 
reached are entirely useless. The flues or tubes in an oven 
fed from the top may be made of any area from one-quarter 
to one-half of one square inch for each pound of wet spent 
tan burned per hour, and if the length of the boilers is pro- 
portioned to the area of the tubes so that the heating surface 
is the same in each case the effect will be the same, but short 
boilers with large tubes or flues are cheaper to build than 
longer ones with smaller flues or tubes. 

Table V. — Area of flues or tubes that is of advantage in burning 

WET SPENT TAN IN ANY KIND OF OVEN, WHEN THE MACHINERY RUNS 

12 HOURS A DAY AND 300 DAYS IN THE YEAR. 

Number of Sides Area of Tubes or 

Tanned Annually. Flues in Square Inches. 

10,000 /. 250 

20,000 500 

50,000 .......1,250 

80,000 2,000 

100,000 2,500 

Horizontal tubular boilers are the cheapest, and if the 
water used is free from sediment or mineral water — that is, 
if the water comes from a clear stream of soft water — will 
last from eight to ten years, but as they contain but little 
water in comparison with the heating surface, must be fed 
often, and are likely to leak or to have the tubes burned out 
if the water is often allowed to get low and then quickly 
pumped up. If the water contains much sediment, or if it is 
" hard/' the tubes are soon covered with a deposit of mud or 
scale. If the deposit is mud the boiler can be washed out, 
but if it is scale from "hard water" in a few years the tubes 
are coated so thick that they have to be taken out and new 
ones put in. 

A tubular boiler of the dimensions given in the tables must 



THE LEATHER MANUFACTURE. 231 

be fed every twenty minutes at least, and will occupy I 
unremitting attention of the fireman or engineer. 

Plain cylinder boilers are the most expensive, but are the 
easiest kept in repair, and the easiest cleaned from mud or 
scale. They have, in addition, the disadvantage of requiring 
a larger boiler house and more expensive setting and founda- 
tions. They contain so much water that they may be 
neglected for several hours without danger, and the steam 
pressure will be more nearly constant than with horizontal 
tubular or flue boilers. 

Horizontal flue boilers are more expensive than the tubular 
and. less expensive than cylinder boilers, and they do not 
require so large a boiler house or so expensive a setting or 
foundation as the cylinder boilers, while they can be cleaned 
and repaired with more facility than the tubular boilers. 
They will last from sixteen to twenty years, or twice as long 
as the tubular. They contain more water than the tubular 
boilers, and (at the rate of combustion recommended in this 
paper) may be safely neglected for at least one hour without 
the water getting too low. If horizontal-flue or cylindi 
boilers are used, they may be connected together in n 
from two to six boilers, and each nest furnished with a feed, 
blow, safety and stop valve. 

The cost of the boiler alone for a 20,000-side tannei . 
will be in 1876 : 

1 horizontal tubular boiler, 54 inches diameter, 12 I I 

long, 43 34-inch tubes, shell | inch, at 10c $700 

Or, 3 horizontal-flue boilers, 40 inches diameter, L6 
feet long, two 12-inch flues, each shell 5-16-inch, 

at7Ac *U 

Or, 4 cylinder boilers, 30 inches diameter, 36 feel 1 

' shell ^ inch, at s| - 1 " 

From this it appears that the flue and cylinder boil 1 



232 THE LEATHER MANUFACTURE. 

nearly the same, but the flue boilers are cheaper to set. On 
the whole, flue boilers are to be recommended as the best 
unless the water is very hard, or unless it is particularly 
desirable to have a boiler that needs very little attention. 

The best way to feed the boiler is by a pump worked from 
the main engine, and the next best way is by an injector. If 
the boiler is fed by an injector the heater to heat the feed 
water by the exhaust steam cannot be used, but this is not 
of importance, as the saving of 10 per cent, that may be 
made by the heater is of no moment when the fuel has no 
value, and the cost of the heater may be transferred to the 
boilers. If the boilers are fed by a steam or other pump the 
heater had better be used, as cold feed water has an inju- 
rious effect on the boilers. If they are fed by a pump worked 
by the main engine it is well to arrange the pump so that the 
stroke may be varied, and to adjust it to work all the time. 

In case the tannery is not located where the spent tan can 
be thrown into the creek, or where there is any market for 
it, tanners will find it cheaper to burn it all rather than cart 
any away. In that case they must provide larger ovens, and 
will not need so large boilers as when they only burn one- 
half. 

The wet spent tan may be burned in this wasteful manner 
(the object being to get rid of and not to economize it) at 
the rate of 30 pounds per square foot of grate per hour, and 
the ovens need to be made one-third larger than given in 
table, for same sized tannery, and the boilers may be made 
one-third shorter, but the diameter and number of tubes or 
flues must be the same, or the diameter had better be one- 
eighth more. The hight and diameter of chimney may be 
the same. That is, the ovens must be one-third longer 
and the boilers may be one-third shorter, if the tanner 
wishes to burn all the tan made, than if he burns only one- 



THE LEATHER MANUFACTURE. 233 

half. In tlits way the boilers are less expensive, but as they 
will wear out (owing to the higher temperature of the gas 
under them) in considerably less time, this arrangement of 
small boilers and large ovens is not to berecomnv nth ,1. 

As an example in the application of the foregoing rules 
suppose it is desired to design a furnace to be fed from top, 
furnish steam for a tannery tanning 100,000 sides of sole 
leather, and running night and day. This would be equiva- 
lent to a 50,000 side tannery running 12 hours a day, and we 
find from the tables as follows : 

Grate surface square feet. 166§ 

Heating surface square feet. 1,250 

Cross section flues. . . .square inches. 1,250 

Diameter of chimney inches. 40 

Pounds wet spent tan per hour 2,500 

The grate surface may be put in two ovens, each 6 feel 
wide and 14 feet long, with three feed holes, each 5 feet be- 
tween centers, or may be put in one oven 7 feet wide and 2 I 
feet long, with four feed holes, each 5 feet between centers. 
The last arrangement would be the cheaper, but the first i- 
to be preferred, because it is well to have a pair of ovens, 
that one may be used if the other breaks down. 

The boiler surface may be obtained in two horizontal 
tabular boilers, each 60 inches diameter and 12 feet l< 
with sixty ?j\ inch tubes, or in four horizontal flue boil 
each 42 inches in diameter and 22 feet long, with two 1 I 
inch flues each ; or eight cylinder boilers, each 30 inch 
in diameter and 36 feet long. 

The chimney would be 40 inches in diameter, or 36 inches 
square. If it were desired to have an oveD fed from the 
front, then the grate surface must be fli«' same, and the hi 
ing surface 25 per cent, more on 1,600 square f< 

The depth of the grate must not be more than t]i<> fireman 



234 THE LEATHER MANOFACTUBr. 

can easily throw the tan. or from 6 to 7 feet, and therefore 
the width must be from 28 ro 24 feet. 

The grate surface could be obtained in two ovens, each 7 
feet deep and 12 feet wide, or in three ovens, each 6 feet deep 
and 9 feet wide. 

The boilers must have 25 per cent, more surface than for 
the oven fed from the top. so that the same boilers as were 
used for the furnace fed from the top will answer if they are 
made one-quarter longer, viz. : 

Tubular boilers 15 feet long. 

Flue boilers 28 feet long. 

Cylinder boilers 45 feet long. 

A still better arrangement would be six horizontal flue 
boilers, 40 inches in diameter with two 12-inch flues. 22 feet 
lonsr. 

In case the oven is fed from the front I consider that the 
grate bars had better be from one foot to one foot and a half 
below the sill of the doors through which the tan is fed. as it 
will be found easier to throw the tan to the back of the grate 
when they are so placed than when they are flush with the 
sill, as ordinarily arranged, and also for the same reason that 
they should be from six inches to a foot lower at the back 
than at the front, in place of being level as usual. The a 
bars are placed flush with the door sill for a coal fire to facil- 
itate cleaning the fire, which never need be done when tan 
bark is burned. 

The furnace doors should be made with a register to be 
opened as the fire may require. 

The ash pit doors should have registers, and the draft 
should be regulated by partly closing the registers in place 
of the damper. 

One of the principal reasons why tan burning ovens often 
fail to give satisfaction is that the joints around the various 



THE LEATHER ilANTTAClTEE. 2 " 

openings and the sheet iron works are poorly made, ai 

air leaks into the flues or chimney and chills the water or in- 
jures the draft. No air should be admitted to mix with the 
after it has left the furnace. 

The space between the bottom of the grate bars an 1 the 
floor of the ash pit should be at least two feet, and may 
as much more as is convenient without detriment. 

The space between the grate bars should not be more than 
| inch, and may be as little as § inch. "With this width of 
space (5 inch) only a very insensibly small portion of the tan 
will fall through into the ash pit. 

It has been customary in furnaces fed from the front to us 
the cone grate bars. I- do not think these are any advant: 
but that the furnace will work just as well with the ordir. 
bars, which are cheaper. 

The grate bars, whether for an oven fed from the top or 
front, may be made much lighter than for a coal fii 
have only to carry a load of about 30 pounds to the - 
foot in place of 60 pounds as in a coal fire, and are n ken 

by blows of the shde bar and hoe in cleaning fire. The]. I 
they are called onto endure is only about two-i 
coal fire, and they may be safely made as light - 
per square foot when 31 inches long. "When the tanner; - 
so situated that it is convenient to burn all the fan the ov 
may be made one-third larger and the boilers with one-third 
less heating surface. The chimney should also be or. - 
larger cross section, in order to avoid danger from - 
Under these circumstances all the steam d - ry will 
made by the boilers, but all the tan made mns 
and the gases will leave the boiler at 
about 1,000°. This tempera hue will set & I 
great care must be taken to keep the fine lead; 
chimney out of contact with all woodwork. 



236 . THE LEATHER MANUFACTURE. 

Six plates illustrating the two kinds of furnaces described 
in this chapter are given in subsequent pages. The first 
three plates, I, II, III, are plans of a set of ovens to be fed 
from the top, which are located at Wilcox, Pa., and used to 
supply steam to the tannery at that place, which has a 
capacity of one hundred thousand hides per annum. These 
ovens and boilers are placed in a building distant three 
hundred feet from the nearest of the other buildings of the 
tannery. 

Plate III, figure 1, shows a plan. In the left-hand portion 
of the figure the roof of the building is supposed to have been 
removed, so that the fire-room floor and the tops of the boilers 
are seen. In the right-hand portion the fire-room floor and 
the boilers are also supposed to have been removed, so that 
the grate bars and the dividing wall under the boilers are 
seen. 

Figures 2 and 3, on the same plate, show east and west 
elevations. In figure 2 the rear wall of the right-hand oven 
is supposed to have been removed, so as to show the boilers 
and the dividing wall between. In figure 3 the front wall is 
supposed to have been removed so as to show the arches over 
the ovens, the grates and the fire-room floor. 

Plate I is a section through one oven and boiler, showing 
the oven ash-pit grate, holes for feeding tan into oven, fire- 
room floor, the boilers, steam drum, mud drum and door to 
enter or sweep out flues in boiler. The two sections of wall 
marked "wall" in the plate are portions of the walls of the 
building, which continue up and support the roof. 

Plate II, figure 2, shows the north elevation, in which the 
door through which the tan is brought from the leaches to 
the fire room is shown by the opening marked 8x10. Figure 
1 on same plate shows two sections, one marked " Section on 



THE LEATHER MANUFACTURE. 2 ', 

(A B)" being through the oven, and the other marked " S ■■• 
tion on (M N) " being through the boilers and brick work 
back of oven. 

The furnace at Wilcox has been selected to illustrate this 
article in preference to a new design, because it is a furnace 
in actual use, which gives perfect satisfaction, and beca 
as it has been already built, the cost is accurately known. It 
will be seen that it really consists of two complete sei 
ovens and boilers, the only thing in common between them 
being the chimney and fire room. Each pair of ovens has 
its own set of boilers, its own feed water tank marked " T " and 
"T"in figure 1, plate III. Either pair of ovens would be 
nearly large enough to supply steam to run the whole tannery 
if the other pair were stopped, either by accident or for repai rs. 
In case, however, only one pair of ovens were used, it would 
probably be necessary to burn nearly all the bark leached, 
while, when both pairs are used, it is only necessary to burn 
about one-half the bark. Each pair of these ovens is prob- 
ably capable (if forced to the utmost) of burning one and a 
half cords of wet spent tan per hour, which would evaporate 
9,000 pounds of steam, being equivalent to about 180 hors 
power. In actual practice at Wilcox they burn one-half a 
cord of wet spent tan each, each pair of ovens per hour evap- 
orating 8,000 pounds of water, being equivalen I to 160 hi 
power from both ovens. This steam runs the whole tannery, 
except the rolling loft. 

The foundations of the ovens and chimney arc not shown 
in the plans. They should be of stone and should go down 
in the ground below the action of the frost. The foundati 
under the chimney, on account of the greal weighl it has to 
bear, should go deeper than this, or at lea t Bis £e< t 1" 
the original surface of the ground, and should b 
larger than the base of the chimney all around. The 



238 THE LEATHER MANUFACTURE. 

step in the construction of this furnace would be to mark 
out on the ground an area two feet larger each way than the 
outline of the building, and then excavate all the earth from 
this space three feet deep. Next, on the bottom of this ex- 
eivation, mark out the position of the walls, and dig a trench 
two and a half feet wide and two and a half feet deep under 
each. Thus there would be four trenches under the four 
walls of the building, and in addition, four trenches parallel 
to the side walls under the four dividing walls of the ovens 
and boilers. The foundation for the chimney will come in 
the center, and should be fourteen feet square and go down 
four feet below the bottom of the excavation, or seven feet 
below the original surface of the ground. The foundations 
under the two wings containing the feed-water tanks may be 
two feet wide, and sunk three feet below the original surface 
of the ground. The walls of the ovens are. commenced on 
these foundations, three and a half feet thick, but with a 
batir of one foot in the hight from the foundation up to the 
level of the fire room floor. From this point they are per- 
pendicular, and of a uniform thickness of sixteen inches. At 
the fire room floor, therefore, the oven walls are two and a 
half feet thick. The walls of the feed-water tank rooms may 
be sixteen inches thick. 

The dividing wall between the ovens has a uniform thick- 
ness of one foot ten inches up to the level of the grate bars. 
The fire brick linings of the ovens commence at the level of 
the grates, and are set back two inches on each side to leave 
a shoulder for the grate bars to rest on. The grate bars are 
each three feet long. One end rests on this shoulder, and 
the other on a wrought iron bar (a worn out piece of railroad 
track answers very well), which runs the whole length of the 
furnace, and is embedded on the walls at each end. There 
are four one and one-quarter inch iron rods, each twenty 



THE LEATHER MANUFACTURE. 

feet long, with a thread and nut on each end, and cas 
washers, through each oven, under this bearing 1 >ar, fco tie th< 
side walls together. The whole inside of the ovens, and the 
tops of the bridge walls, and the inside of the walls und< c 
the boilers, are lined with fire brick. The holes for feeding 
the tan through the top of the arch into the oven are lined 
with fire brick which must be made of the required shape by 
the manufacturer. The side walls of the ovens rise verti- 
cally for one foot, and are then turned into a circular arch of 
three feet radius. The lining of this arch should be of fire 
brick not less than six inches thick, and there should be in 
addition two courses of common brick, so that the whole 
thickness of the arch is fourteen inches. The fire room floor 
may be of brick, laid on edge, and the space between the 
arches under the floor filled up with broken bricks and mor- 
tar. There are four doors through each outside wall of the 
ovens. These must be made with arched tops of fire brick, 
made the exact shape by the manufacturer. 

The owner of the furnace will find it to his advantage to 
have the brickwork around the ovens constructed with gri 
care, as if carelessly built it will crack, or even fall down, in 
a few years. The heat in one of these tan-burning ovens, 
although not so great as in o, coal fire, is greater than in the 
ordinary furnace when the grate to burn the coal is under the 
hoiler. Apian of the grate bar to be used is shown in figure 
3, plate V. These grate bars may be much lighter than 
when used for coal. The oven doors should each have a 
register in them, to be partly opened to admit air above fche 
fire when the oven is in use. 

Through the courtesy of Mr. Judson Schultz, of Wil< 
Pa., I am enabled to exhibit the exact msl of tin's furnace in 
1872. At the present time (September, 1876) the coal would 
probably be 25 per cent. less. 



240 THE LEATHEE MANUFACTURE. 

COST OF FURNACE AT WILCOX, 1872. 

Brickwork — 

Chimney— 35,000 bricks, at $6 00 $210 00 

Two masons, 20 days, at $5 00 per day 200 00 

Three helpers, 20 days, at $1 50 90 00— $500 00 

Ovens and Walls— 112,500 common brick, at SG 00 675 00 

5,800 fire brick, at $60 00 348 00 

One-quarter-circle bricks, for arch 100 00 

Three masons, 52 days each, at $5 00 per day 780 00 

Two helpers, 50 days each, at $1 50 per day 150 00 

Digging foundations, hauling stone and sand 300 00 — 2,353 00 

Boilers Etc.— 

Six boilers and standards, with two mud drums 3,575 57 

Four furnace doors, four back connection doors, four doors 
to enter under boiler, two smoke jacket doors, one 

chimney door, 5,536 lbs, at 5%c 303 48 

Back stays, 8,062 lbs, at 5c 403 10 

2,048 grate bars, 26,175 lbs, at 4%c 1,177 88 

Washers, 130 fts, at 5%c 7 15 

Dampers and smoke jacket 58 00 

Tie rods under grate 100 00— 2,049 61 

Hoof— 

3,000 feet of lumber for rafters, at S10 00 30 00 

Labor 50 00 

Sheet iron 325 00— 405 00 

Total cost of oven and fixtures $8,883 18 

Taking the total cost at $7,000, it will appear that the 
original investment in the furnaces will be at the rate of 7 
cents for each hide tanned annually, and that at 15 per cent, 
(allowing 7 per cent, for interest on capital, 3 per cent, foi 
annual repairs, and 5 per cent, for a sinking fund), the annual 
cost will be $7,000X-15— $1,050, or about one cent for each 
hide tanned. 

If it were required to build a cheaper furnace than that at 
Wilcox, the brick walls above the ovens and boilers and the 
iron roof may be omitted, and wooden walls and a wooden 
roof used in their stead. 

If tubular boilers in place of flue boilers are used, the cost 
of the boilers will be less, and the brickwork setting will cost 
less. 

If the feed water is free from sediment and scale, tubular 
boilers will be just as economical as flue boilers, but will not 



THE LEATHEE MANUFACTUEE. 211 

Inst so long, and will need more unremitting attention on tlie 
part of the engineer to keep the water at the correct level. 
On the whole, they are not to be recommended. 

Plates IV, V, VI, represent an oven for burning wet spent 
tan when the tan is shoveled in to the oven through an 
ordinary furnace door like coal or wood. 

P.'.ate V is a section through the center of oven and middle 
boiler, showing the oven grate and ash pit, the boiler, steam 
and mud drum, and the front and back connections. 

Plate VI, figure 1, represents, on the left hand portion, an 
elevation of the front of the oven, showing one furnace and 
one ash pit door and half of the middle furnace door, and mi 
the right hand portion a section through the oven showing 
the top and sides of the oven, the thickness of the brickwork 
and the grate bars. Figure 2 is a section through the boiler, 
back of the oven, showing the three boilers and flues, tin 
steam and mud drum and the thickness of the brickwork. 
The unshaded bricks represent the fire brick in all thre 
plates. Furnaces fed from the front like this are generally 
considered cheaper to build than those fed from the top, but 
this is because they are generally made smaller in proport i< >n 
to the size of the tannery than those fed from the top, and 
are therefore ordinarily much less efficient. 

If both furnaces are built of the size required to give the 
best results, the furnace fed from the front will require to be 
the largest and will cost the most. 

The construction will be readily understood from the plans. 
The plan of the grate shown in figure ::, plate V, has been 
found in practice to be strong enough. There are two Lengths 
of these grate bars, each 2 feet 8.1 inches long. The back 
length is level, but the front length should be raised from -i\ 
to eight inches in front to facilitate feedini tip' tan toward 
the back. The ends of the grate bars must be carried by 

16 



242 THE LEATHER MANUFACTURE. 

wrought iron bars, reaching across the oven and built into 
the brick work at each side. An old piece of railroad iron 
will answer, or a piece of wrought iron four inches deep and 
one inch thick. 

The furnace and ash pit doors may be made of a piece of 
boiler iron a quarter of an inch thick, with the hinges and latch 
riveted on. The lugs to carry the hinges, and the latch, may 
be built into the brick wall, thus dispensing with the cast- 
iron door frames. The furnace door should be double, the 
inner lining of boiler plate being punched full of quarter inch 
holes two inches apart. Both the ash pit and the furnace 
doors should have openings through them with registers. 

The three furnace doors should be each 20 inches wide and 
18 inches high on the outside, spreading out wider on the 
inside, as shown in the plan, plate IV. The ash pit doors 
should be 16 inches wide by 24 inches high in the clear. The 
fire room floor should be 24 inches below the si 1 of the fur- 
nace door, or 18 inches above the bottom of the ash pit, as 
the fireman can shovel in the tan easier than if the floor is 
as low as the bottom of the ash pit. 

The brick work around the oven must be tied up with buck 
stays and iron rods, as shown in the plans, for as the arch 
over the top of the oven has a wide spread, it exerts a great 
pressure on the side walls. Also the fire bricks in the arch 
must be laid with care with narrow joints, or the}' will fall out 
after the furnace has beon a little while in use. 

The smoke connection in this furnace is shown in plate V, 
as built of brick running across the boilers over the top of 
the oven. This connection must lead to the chimney built 
on either side. The chimney should be eighty feet high and 
twenty-four inches in diameter. The back ends of the b< >iler 
are carried by the mud drums, and the front ends by a piece 
of railroad iron built into the brick work over the oven. 



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THE LEATHER MANUFACTURE. 



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ILLUSTRATIONS. 



248 THE LEATHER MANUFACTURE. 

Until within a few years it lias been considered indispen- 
sable that the " sweat pits " of the tanner should be under 
ground, but now they are placed on the top of the ground, 
with earth or some other non-conductor surrounding and 
covering them. It is far more desirable that the bottom of 
the pit should be on a level with the beam house floor, or 
so nearly so that a wheelbarrow can be run from one to 
the other, than that there should be an earth or rock excava- 
tion surrounding the pit as was formerly thought necessary. 
The present plan enables the pits to be properly lighted both 
from the ends and tops. 

These pits should be large enough to properly hang one 
pack each, whatever may be the size of that pack — usually 
from 100 to 200 sides. The ceiling should be at least eight, 
and if ten feet high all the better. There should be a space of 
at least two feet from the lower portion of the sides, while 
hanging, to the floor, for the purpose of allowing the free in- 
troduction of steam under the pack, if the pit is too cold, and 
of cold spring or well water if too warm. The temperature 
should be about 60 to 70 degrees. The air should never be 
dry, but kept moist by the introduction of steam or cold water. 
Usually the atmosphere will regulate itself. The wet pack, 
hung in an atmosphere of 65 degrees, will impart its moisture, 
which will condense so that drops of cold water will stand 
on the surface and show on the hair of the hide, precisely as 
from the ox when profusely sweating from over exertion. 

The mode of hanging will vary with the judgment of the 
tanner. Some hang over sticks, others hang from tenter 
hooks. But whatever way hung, the sides or hides should 
be so placed that the attendant can readily reach each side, 
so that as soon as the hair of even one side or hide begins 
to " come " it should be dropped to the bottom, and when 
that of a majority of the pack " starts " they should be re- 



THE LEATHER MANUFACTURE. 



2 




49p 

VIEW IN PERSPECTIVE — SHOWING INSIDE OF TWO END I 





■ i!t 1 , :f. 



If 

i 



! | *■ 






INTERIOR VIEW OF SWEAT PIT. 



250 THE LEATHER MANUFACTURE. 

moved ; but if proper care has been taken to have the whole 
pack in the same condition and of the same weight and sub- 
stance the whole pack will come out about the same time. 
From five to seven days' time will sweat an ordinary dry hide 
in one of these pits. The ventilation of these pits should 
always be under the control of the attendant. 

One of the views presented gives a lengthwise view of sev- 
eral pits, and the other that of a single pit as seen from the 
door. 

THE "SHOVER" HIDE MILL. 

The three sectional plates herewith given present a fairly 
intelligent working plan of the ordinary " fulling stocks " for 
softening hides. This form of mill has so completely taken 
the place of the old-fashioned " falling stocks " as to render it 
unnecessary to present a drawing of that discarded machine. 
The capacity or power of this mill to soften dry hides is 
almost without limit. One mill of the size here contemplated, 
run at the rate of sixty to eighty revolutions per minute, will 
soften 1,000 hides of ordinary weight in one week, running 
for twelve hours per day. It is within the writer's knowledge 
that a mill of this description has been made to soften 100,- 
000 dry hides in one year, being run night and day. 

In the drawing this mill is geared from above, but the 
power is often attached from beneath, and where this can be 
done it has the advantage of greatly facilitating the workmen 
in feeding the mill and handling the hides. "With the latter 
attachment the arms of the mill are extended down through 
the hammers, and the bottom of the mill and driving shafts 
are attached below, just as they are represented in the draw- 
ing to be attached above. These mills, as formerly made, 
of hard wood plank, would wear out with one year's constant 
service; but lined and faced with cast and wrought iron, as 



THE LEATHER MANUFACTURE. 

a. a, 



25] 




THE HIDE MII.1-. 



252 THE LEATHER MANUFACTURE. 

is now customary, they will last for many years. The form 
of the mills varies slightly with the different makers, and 
the size as well. Tanners who are about to adopt this method 
of softening hides will do well to examine with care the most 
approved angles and motion of mills now in use in our best 
yards. The double action of these mills is as well adapted 
for skins and pelts of all kinds as for dry hides. There can 
be no doubt that from this form of mill the idea of the mod- 
ern "washing machine" was taken, and in turn the tanner 
is indebted to the clothiers, and chamois and oil dressing 
leather manufacturers for the ideas contained in this most 
efficient hide softener, for with some variations of form it is 
a reproduction of the fulling stocks of the clothier a century 
ago. It was introduced among American tanners about the 
year 1830, at Salem, Mass., and did not find general accept- 
ance among hemlock tanners in the State of New York until 
1850. 

THE HAND REEL. 

On the opposite page will be found a representation of a 
hand reel, which is commended in Chapter VII., on " hand- 
ling." The facility with which packs may be thus trans- 
ferred from one vat to another commends this skeleton reel 
to all tanners. It is safe to estimate the performance of this 
machine with two men as equal to that of six men by the old 
hand process. Besides, it does not require either man to 
stoop in his work, and the labor is therefore much easier. 
The stand and skeleton drum should be made of as light 
material as possible, so that its transfer from one vat to 
another may be effected by the two men with ease. As there 
need be but one of these reels in any ordinary sized tannery, 
the tanner can well afford to have the frame, drum and bear- 
ings made of substantial but light materials, well adjusted m 



THE LEATHER MANUFACTURE. 



2500 



w 
u 




; /yf\/ 



254 THE LEATHER MANUFACTURE. 

all parts, even with brass bearings. The whole need not 
cost oyer ten dollars. 

If still more ecouomy of labor is required, these reels may 
be driven by power from shafting and pullies permanently 
running overhead. But it will be found that two men can 
shift ten thousand sides in ten hours without the use of 
power. 

The sides may be tied together with strings or connected 
with a tie-loop ; strings are preferable, and are quite inex- 
pensive. 

THE LOCKER HANDLER. 

The accompanying drawing will serve to give a correct 
idea of the rocker handler, which is now held in such high 
esteem. 

The gentle and intermittent motion required should be 
given from shafting from above. This shafting should run 
over the center aisle, and have projecting arms, from which 
there should extend a connection to each of the frames of the 
rockers. This connection may be by a pole or strip of plank 
two inches square, made of any tough timber, and so ad- 
justed as to be readily disconnected. The vibration of the 
rocker on which the leather is hung should not be over four 
or six inches, thus causing as little agitation of the liquor as 
is consistent with a gentle movement of the fiber of the green 
stock. (See Chapters VII. and YHI.) 



THE LEATHER MANUFACTURE. 



- 



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256 THE LEATHER MANUFACTURE. 



THE AMERICAN LEATHER ROLLER. 

The skeleton drawing on the opposite page represents the 
universal American roller. The only patent now existing on 
this roller, as here presented, is on the leverage under the 
table. The whole cost of this leverage is $30, on which there 
may be a profit of $10 for the patentee. The roller bed is 
made of wood or metal ; the one in the drawing is made of 
copper. It is cast hollow, and is valued at about $40. The 
whole machine will cost about $200, including the woodwork, 
table, etc. Such a machine will roll about 100 sides each day 
of ten hours. 

The amount of pressure which can be brought to bear on 
the side has absolutely no limit. It is claimed that a side of 
sole leather can be cut in two if the whole power of the lever 
is evoked. 



THE LEATHER MANUFACTURE. 



257 




17 



258 THE LEATHER MANUFACTURE. 

The representation on the opposite page shows the new 
form of dryer, now so generally in rise. The building may 
be of any hight or shape ; the engraving is of a structure of 
four stories, besides the basement floor. This lower story 
should be reserved for steam pipes, or other means of head- 
ing. All the floors above are latticed, and when not 
obstructed by dampers, allow the free passage of air to the 
top opening. The draft may be regulated by " stops " or 
"clampers," either at the openings on the lower floor or at 
the top openings, or both, the object being to absolutely con- 
trol the currents of air, so flat only so mvch, and at such periods 
as the attendant may desire, iciV air he allowed to pass. If 
glass windows are used, as shown in the drawing, they are 
only to give light to enable the work to be done, but never 
to be opened for the purpose of admitting air or light to reach 
the leather, and when the work is done they are to be covered 
with a window shade, so that the leather may be excluded from 
the light during the whole drying process. This form of dryer 
is built on the plan of a chimney, and the laws of its action 
are precisely like those of that essential ventilator to our 
dwellings ; if currents are permitted to enter otherwise than 
at the bottom, counter currents will be formed in the dryer, 
and it will not " draw," but if the air is confined, then the 
difference between the temperature of the air at the ground 
and that at the elevation at the outlet will cause the current 
to rise, and rapidly just in proportion to its hight. Hence, 
to get a satisfactory self-acting turret, the building should be 
as high as possible. For more specific suggestions regarding 
the economic use and management of these dryers see Chap- 
ter xn. 



THE LEATHER MAKUFACTUEE. 



25! 




THE TURRET DRYER. 



260 THE LEATHER MANUFACTURE. 

THE ALLEN' & WARREN SPRINKLER LEACH. 

This is a "percolating" process of leaching bark in contra- 
distinction from the " press " system. Both methods are in 
very general use in this country. The Allen & Warren 
method is known as the " sprinkling" process, and is shown 
in the drawings. Many tanners, however, accomplish imper- 
fectly a similar result by flooding their leaches with a limited 
quantity of liquor, allowing it to percolate through, and then 
flooding again and again, each time with about one-third of 
a vat of liquor. But if percolation is to be practiced at all, 
there can be no doubt that the Allen & Warren method is to 
be preferred. 

This sprinkling process has been so much abused by tan- 
ners, and so much damage has been done thereby, both to the 
color and general quality of the leather, that a strong preju- 
dice exists in the minds of many against this method of leach- 
ing ; but it is believed that if the new bark is leached with cold 
or only warm water or liquor, then a concentrated and pure 
liquor can be obtained, while if the head liquor is heated up 
to, or near, the boiling point, and is then sprinkled on the 
new bark, an undue amount of coloring matter will be carried 
down and find its place on the leather, making both a dark 
color and a harsh texture and fiber. The practical working 
of these leaches proves that " strength " can be more concen- 
trated with them than by any other means; hence, for extract 
manufacturing, they are serviceable, and we should judge 
that fully one-half of the hemlock tanners of the country are 
using them, without appreciating their good qualities or 
avoiding their bad ones. 

The heater box, by which the exhaust steam from an en- 
gine will heat a constant stream of water or liquor without 
in the least reacting upon or retarding the power of the en- 
gine, may be seen in the two lower engravings. The sec- 



THE LEATHER MANTJFACTUBE. 



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THE SPRINKLER LEACH. 



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2C<2 THE LEATHER MANUFACTURE-. 

tioual figure represents two shelves, c and d. These are set 
on an incline, so that the water or liquor, which enters at a, 
tills the compartment b, until it overflows on the inclined 
shelf c, passes down on the inclined shelf d, and so finally 
out of the discharge opening e. The steam from the engine 
takes the opposite course, entering at f, passing through the 
liquor or water until it finds its way out at g. The steam 
thus passing will fully condense, and only moderately-heated 
air will pass off. The other drawing represents the enclosed 
box, with these shelves inside. 

By this simple and inexpensive construction of plank a 
most effective heater is made, and by its use a constant 
stream of hot wafer or liquor can be run through on to 
the leaches. 

If the most perfect heater possible is desired then small 
holes may be made in the shelves, in which case they should 
be made of copper plates — then the perforations can be small 
and effective ; they will rain down small drops, condensing 
the steam most perfectly. This is one of the best and most 
effective improvements ever made in the heating of liquors. 
There is no patent claim on this improvement. 

THE BARK CUTTING MACHINE. 

The accompanying cut is designed t > show the new ma- 
chine for sawing tanners' bark. There can be no doubt that 
this machine does prepare bark for leaching better than any 
known bark mill of ordinary construction. It will saw damp 
or even wet bark with the same facility as if it were dry. If 
the bark is in large pieces it can be fed into the mill with 
facility, but if small then it will require a hopper or some 
other contrivance not yet perfected, certainly not practically 
introduced, to facilitate the feeding. It is claimed that a 
single mill will cut one cord and a half per hour. To do 



THB LEATHER MAM"FAi"TUttK. 



M» 




BARK CUTTING MILL. 



264 THE LEATHER MANUFACTURE. 

this we should judge that the circumstances must be very 
favorable. 

The high cost of this mill, $300, will probably restrict its 
use ; it is, however, far better for tanners to pay even this 
price, unless it is possible to secure an equally good result 
by some more economical method. That other method is, in 
our judgment, by the use of a wire screeu, as expressed else- 
where. There is no excuse for attempting to leach coarse 
and unevenly ground bark. 

THE KEYSTONE BARK MILL. 

The skeleton form of bark mill presented on the opposite 
page is probably the most skillfully manufactured machine 
of the kind known to the trade. We have taken special pains 
to describe its peculiar construction and its performance 
in chapter V, to which the reader is referred. Great pains 
are taken to make this mill run true ; the ability to replace 
the surface segments, by either steel or cast iron surfaces, 
renders it one of the most serviceable, and, when we consider 
the safety coupling with which it is connected with the driv- 
ing shaft, it is one of the most durable mills known. If tan- 
ners either cannot or will not adopt the wire screen, then we 
say this mill will grind more uniformly than any mill offer- 
ing to the public, but it will not grind wet bark any more 
than will other cast iron mills. 

THE HOWARD SCRUBBER. 

As the drawing indicates, this scrubber consists of two 
skeleton drums, with projecting arms, into which are fastened 
birch brooms, closely held. The drums are rolled together 
by the cog gearing as seen on the side. When ready for work 
the box or covering marked A is dropped down, and through 
the slit or opening, G, the sides are fed. The feeding is per- 



THE LEATHER MANUFACTURE. 



2G5 




ALLENTOWN BARK MILL. 




HOWARD LEATHER WASHER. 



266 THE LEATHER MANTTTACTURF. 

formed by allowing one end of the side to pass down between 
the revolving brushes ; if the side is fir inly held and allowed 
only to pass down slowly the surfaces will be thoioughly 
scrubbed, and well done ju-t in proportion to the time al- 
lowed. To do the work well each side must be passed 
through twice, once from the head and once from the butt. 
One of these machines with two men to attend it will scrub 
about four hundred sides per day. It is simply justice to say 
that the " drum scrubber," elsewhere described, is taking the 
place of this Howard machine in some of our large hemlock 
tanneries, and tanners will do well to examine the inerits oi 
both before adopting either. 

THE SALEM WET TAN PRESS. 

This lever roller serves a most useful purpose for squeezing 
out the remaining ooze from spent bark, previous to burning 
it. Just to the extent that water or spent ooze is taken from 
the bark is the bark rendered serviceable to burn. It is now 
demonstrated that Thomp-on's patent for burning water, 
(which is equivalent to saying that wet tan will give more 
heat than dry tan), is a fallacy. But whether the power lost 
by squeezing out the water is not the equivalent of power 
lost in drying out the water in the oven is a question never 
yet determined by actual experiment. 

This Salem machine is fully as efficient as the French and 
English machines for the same purpose, and seems more sim- 
ple in construction. It is regarded a8 serviceable where the 
tanner requires more power than he can gain by the use of 
wet spent tan burned in an ordinary oven ; but all sole lea- 
ther tanners have an excess of tan, and, therefore, can never 
require this vat tan squeezer. 



THE LEATHER MANUFACTURE. 



267 




THE SALEM TAX PRESS. 



268 THE LEATHER MANUFACTURE. 



THE LOCKWOOD AUTOMATIC LEATHER SCOURER AND HIDE WORKER. 

On the opposite page is an illustration of tliis new inven- 
tion, patented July 26th, 1876. The machine is novel in 
construction, simple ia its movements, and ingenious to the 
extent of almost running itself, as the weight of a man's finger 
can guide the scourer over the surface of any kind of thick or 
thin leather. The patentee claims it to be a machine complete 
in itself, independent of building or framework ; it can be set 
up without bolting or bracing, is durable, being made of metal 
of the utmost strength, and with air cushions which relieve 
the working parts of thrusts and strains. The machine can 
be set at any angle with the line of shafting, and belted 
on either end from above or below. Onlv from one to three 
horse power is required to run it, according to the thickness 
of leather being dressed. It occupies but little more space 
than an ordinary currier's table. It seems almost automatic 
in its movements, and is capable of the widest range of work, 
from the lightest to the heaviest ; will scour, set out or glass, 
and can be made to take a slow or quick stroke, a long or a 
short one, making the most perfect stroke attainable with 
the smallest Joss of motion, which is effected by the epi-cycle 
and cam combined. 



THE LEATHER MANUFACTURE. 



269 



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B 

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EU 

cc 
o 
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ej 
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270 THE LEATHER MANUFACTURE. 



THE FITZHEXRY SCOURING MACHINE. 

This machine has been so universally adopted, riot only 
in this country but throughout Europe, that it is perhaps 
doubtful whether it should not be excluded as one of the old 
inventions, too well known to be entitled to a place in this 
volume, which claims only to present novelties, or such ma- 
chines as are confined in their use to localities, and are com- 
paratively new. But since within a few years we have an- 
other, and within a few months still one more, competitor for 
the honors of recognition, all three are given in contrast. 



THE LEATHER MANLTACTUEE. 



£71 




272 THE LEATHER MANUFACTURE. 



THE BURD0N SCOURER. 

This practical and very serviceable machine is mostly use- 
ful in scouring out bloom, while it at the same time softens 
and cleanses the grain. It is useful for harness leather and 
fair leather curriers, but has not so far proved a success in 
scouring sole and belt leathers, which require more vigorous 
treatment. For calf, sheep and goat it should answer a most 
valuable purpose, and for grain leather it must prove a very 
efficient machine. 

The high cost of the machine has no doubt prevented its 
adoption more generally by the trade. Had the improve- 
ment fallen into other hands', there can be no doubt that it 
would have come into general use before now. 



THE LEATHER MANUFACTURE. 



273 




THE BUEDON LEATHER BCOURER. 



13 



274 THE LEATHER MANUFACTURE. 



THE STUFFING WHEEL. 

The accompanying drawing presents one of the commonest 
forms of the stuffing wheel, now in very general use in ihis 
country. Through the opening door may be seen wooden 
pins on which the leather falls in the revolutions of the 
wheel, and they also serve the purpose of carrying upward 
the sides or skins, and generally agitating the fiber. This 
wheel may be driven by a belt, as shown in the drawing, or 
by cast iron gear. 

The general methods of using this wheel have already 
been discussed in the preceding chapters. It was first prac- 
tically introduced by Mr. Charles Korn, as early as 1856 to 
1860. It had its origin in Germany, but there a barrel or 
hogshead served the purpose, while here special wheels of 
permanent construction were first introduced into Ihe curry- 
ing shop of Mr. M. M. Schultz, in the year 1860, at Sparrow- 
bush, N. Y., under the direction of the original introducer. 

This wheel has revolutionized the character of the upper 
leather of the country, which is now made soft and yielding, 
whereas before it was hard, the oil and tallow being now 
fulled into the center of the fiber, while under the old method, 
which applied the stuffing on the flesh side, it only penetrated 
a little beyond the surface, leaving the main body of the 
leather dry and unaffected. Leather prepared for this wheel 
should be in the same condition as to dryness as if stuffed 
on the surface in the ordinary way — neither too wet nor too 
dry. 



THE LEATHER MANUFACTURE. 



27£ 




THE STUFFING WHEEL. 



276 THE LEATHER MASTCJFACTURE. 



CHARLES KORN S WHITENING MACHINE. 

The accompanying illustration shows Mr. Korn's whitener, 
with the inventor operating it. The action of the machine is 
precisely that of a currier's knife in the hands of the work- 
man by Ihe ordinary beam process. The knives are fastened 
to an endless leather belt, and set diagonally, so that when the 
cut is made on the beam, as it passes down in front of the 
operator, there is a sliding and diagonal cut. The knives (for 
there may be as many as you please, certainly three or four) 
are cleared on their edge by one moving automatic finger, 
and by an automatic hand the edge is sharpened. This lat- 
ter performance is the most complete success, performed by 
the most ingenious piece of mechanism, the writer has ever 
seen. Ihe inventor claims that he can, with this machine, 
do the work of four men, and do it better than by hand work. 



THE LEATHER MANUFACTURE. 



277 



a 
;> 
w 
t-t 

W 

o 

H 







278 THE LEATHER MANUFACTURE. 



THE "UNION LEATHER WHITENING, BUFFING AND SKIVING MA- 
CHINE." 

Herewith is presented a representation of a recently in- 
vented machine for whitening, buffing and skiving leather. 
It is simple in construction, easily kept in order, requires 
from four to five horse power to run it, according to the 
thickness of the leather, and requires only an ordinary oper- 
ator to perform as much work in one day by the use of the 
machine as is usually done by four whiteners. The quality of 
work is uniform and equal to that of the best skilled hand 
labor. The knives or blades make clean cuts, leaving no 
nap, and the leather, when finished, is smooth in the flanks, 
bellies and necks. The cylinder contains thirty-two knives 
or blades, inserted spirally, and a sharpener is attached, 
which travels forward and backward across the edges of 
the blades. The cylinder revolves 2,780 times per minute, 
and the pendulum swings to and from the operator at a speed 
of 90 per minute. 



THE LEATHEB MANUFAOTUBE. 



279 




INIOX WHITENEB AND BUFFING MACHINE. 



280 THE LEATHER MANUFACTURE. 



FISK'S WHITENING AND BUFFING MACHINE. 

The inventor claims that this machine can and will do its 
work much more economically and even better than can be 
done by hand labor. Among its claimed advantages are the 
following: "It is small and compact," "runs with small 
amount of power," and " the table has a convex bed, and 
thus bends the surface of the leather from rather than tow- 
ard the cutter" — "consequently," says the inventor, "the 
square edges of the blades take hold of the leather with very 
little pressure, and make a light, clean cut." Some certifi- 
cates of those who have used the machine assert that wax 
leather, measuring from nineteen to twenty square feet per 
side, can be whitened by it in from one and a quarter to one 
and a half minutes, thus making about forty sides per hour. 
This, no doubt, is an extreme performance. 

The general resemblance of this machine to " the union 
leather whitening machine," presented on another page, 
will strike all who compare their general structure. The dif- 
ference consists in the working of the table, or the feeding of 
the knives. The knives themselves, and the form of sharpen- 
ing them, may be considered identical. There can be no 
doubt that this machine does good work, and far more eco- 
nomically than it can be done by hand labor, so that it will 
probably share the patronage of all tanners and curriers who 
profess to study the economies of their trade. 



THE LEATHER MANUFACTURE. 



281 




FISK S WHITENER AND BUFFING MACHINE. 



282 TIIE LEATHER MANUFACTURE. 



"THE UNION LEATHER SPLITTER," 

shown on the opposite page, is too valuable to omit from any 
classification of American leather dressing machinery. It 
was the pioneer of all the improvements made. While we be- 
lieve there are yet patents maintained on some unimportant 
parts of the machine, as a whole all patents have long since 
expired. 

This machine has revolutionized the currying and finishing 
of leather in America, and is destined to do so in every other 
country. No currier can afford to carry on his business 
without a splitting machine of some kind, and this union 
machine is both the cheapest and simplest in construction. 

THE LAMPERT HIDE WORKER. 

This eccentric machine is well designed for unhairing 
hides or skins. The drum "A" revolves on the axis " B " at 
the center, rendering it unnecessary to move the hide side- 
ways, but by a slight effort of the hand the drum is rolled 
from right to left, or left to right. The hide is drawn toward 
the workman as the parts become finished, whether the 
machine is used as a scourer or unhairer, for it is capable of 
doing any work which can be done with the worker. Tin- 
stone or slicker is held by a steel spring, which in turn is 
propelled by the arm attached to the balance wheel. The 
machine should be seen in operation to be fully appreciated. 

Eccentric motions are now used very extensively in several 
departments for the finishing of leather. Grain leather of 
all kinds is diced, and morocco and sheepskins are glazed 
and polished, as well as diced, by machines which use eccen- 
tric motion, with modifications of form and action. 



THE LEATHER MANUFACTURE. 







UNION LEATHER SrLITTER. 




HENRY LAMrEKT'S HIDE Wo] IK Kit. 



284 THE LEATHER MANUFACTURE. 



OUTLINE OF HIDE WITH TRIM USUALLY MADE. 

The cutting of the hide in forms has become so common, 
from the demands of the belt, harness and shoemakers, that 
we have availed of the accompanying cut to locate each part 
by a designated term. This nomenclature conforms in part, 
if not altogether, to the English classification. "A A" are 
the bellies; "B B" are the bends; " <7" and "Z>" are 
shoulders. Sometimes the shoulders are cut so as to in- 
clude the neck, and in that case both " (7" and " D " are cut 
in one piece, but it is more common to cut " C" as the shoul- 
der. This trim will be varied by the fact as to whether the 
hide is a "cut" or "stuck" throat. The term "offal" ap- 
plies to all the parts outside of the bends marked " B B," 
but the pieces are separately and specifically named as 
above. 



THE LEATHER MANUFACTURE. 



liS.I 




OUTLINE AND TRIM OF BIDE. 



286 THE LEATHER MANUFACTURE. 



TANNERS' AND curriers' TOOLS. 
On the following page is a representation of a case show- 
ing the principal kinds of tanners' and curriers' tools in use. 
The center piece is a moon knife, and around this the others 
are arranged, in most attractive form. The two long, thin, 
straight knives, extending from the center toward the right 
and left hand upper corners, are the recently introduced Ger- 
man fleshers, which have of late attracted so much attention. 



:he leather manufacture. 



2S7 




tanners' and curriers' tools. 



Plati 



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Plate II. 




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Plate III. 



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Plate IV. 




Plate V 




Plate VI. 



DESIGN for FURNACE for burning "WEST-SPENT-TAN" 



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ELEVATION a- SECTION TH ROUGH OVEN. 




SECTION THKOt/GH BOILER 



AOMPTED TO BORN (-^ COrTO Ar*» TO ronirHS* /6GO fountii O^STfAfV) 



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M )| . J600 - ■ J P£ff HOOK. 

'Ae/orq- -rue Size RccViVHVie ro* * 3oic'£-S*>TMi?/1 72,/M£*jr TMiYPfitrQ -ZO.GjO SrO£6 

WHEN THE ty/HCH'IVCrtY /TUNS /2 HUW-1 »> B*X oj rvft OOVBIC TMHT CHFACirjr ( 4>&.CJOC 

When the Nif^n/rvefty rja/rJ -?y hooks h-oh!/ 



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INDEX. 



A 

Acid, use of in handling 76 

in old liquors 83 

Agitation of the fiber of hides and 

skins promotes rapid tanning. 183 

Alkali for removing white spots 90 

Ammonia in old limes 32 

Army officers, prejudice against hem- 
lock leather 107 



B 

"Baggy" leather made by vacuum 
tanning 182 

Bark dust 51 

to suppress 130 

Bark elevators choking 139 

Bark, extractive and coloring matter 

with tannin in 55 

Bark grinding 46 

it should be ground fine and even 47 

grinding damp or wet bark 50 

screening ground bark 50 

E roper degree of fineness 51 
enuock '. 156 



Bark rossing Ill 

oak 159 

Bark mills— the "double grinder" is 

the Allentown mill. 49, 265 

the saw cutting mill 51, 262 

crushing machine 52 

capacity of different mills 53 

speed to run mills 53 

Bating with warm water and hen 

manure 31 

after liming si 

Beam work 88 

Blacking, flesh 221 

"Black rot " in sole leather 89 

Bleaching leather ion 

Birch bark tanning 169 

Boot and shoe industry of the Dnitecl 
States according to the census 

of 1870 244 

Box vats 122 

"Buffalo"vats 121 

Buffing and whitening machines 

41, 276, 278, 280 

Buff leather 210 

Burning wit sjn-nt tan, the first suc- 
cess in 117 

Burning wet tan 47. 224 



302 



INDEX. 



E 



Calfskins, French and German. .. . . .1W 

the best goods made sent to Great 
Britain and the U. S. .... •• ■!•» 

care in assorting the green 8tock.l9o 

soaking and milling J™ 

breaking the nerve |» ' 

liming andunhairmg j»» 

bating • • • onn 

coloring and handling. ^"" 

grain to gram . 



East India kips • • •■ • • • • • .V 191 

Elevator for raising leather to t 

drying loft 

" England " wheel, the. ... . • • 
Experiment with water and tan liquor 63 
in tanning New York City hides.. 8a 
in tanning by hydrostatic pres 
sure 



115 

73 
63 



177 



laving away, B 

Sffig 6 . 8 --""- •■" ~ ::202 I Ferguson, Thomas T., experiment at 

louring 203 I Sparrowbush, N. ¥., on vacuum 

stuffing 



.204 
.205 



slicker whitening 

boarding......... gg 

kept in russet state. . . ._ £»> 

palm oil used in currying ....... iU7 

Census of 1870, boot and shoe mdus- 

trv of the United States ... . . . -.244 

leather industry of the Lnited 

States in 1870..... .....245 

Chimney, dimensions of for wet tan 

ovens •••• „q 

Clayfor a tannery foundation. 119 

Clewer, James', method of leaching. 57 
Climate and food, effect of on hides. .189 
Color, a natural hemlock desirable. .10o 
Color of hemlock leather improved by 

sumac , , . , ' , ."v"i'a 

Coloring and resinous matter in bark ob 
Coloring of leather to be done in the 



17Q 
tanning *'* 

Fertilizing liquids £** 

Flesh blacking ■ • *j± 

Fleshing, cost of thorough work 3« 

lime slaughter stock •*■* 

before liming *" 

sweat stock j' 

the German fiesher .. • • • ■• ** 

Fisk's whitener and buffing machine. 280 

Furnaces, directions for constructing 

for burning wet tan M* 



handlers. 



108 



Concentrated liquors obtained by the 

sprinkler leach : •• • bb 

Conductors of liquor decay rapidly 

when above ground. ......... .1^1 

Cost of boiler for 20.000-side tan- 

nery 

Cost of furnace at Wilcox, Pa. .... . .240 

Cost of tanning, the lba ' ™ 

" Cropping " leather *i 

"Cuir" color....... «» 

Currving and finishing f 1 " 

Cutch 1M 



D 



Dampening before rolling 97 

Degras in making stuffing *■£ 

Divi divi • •• • • • • • • ij:;-„ ' 

Domestic hides of the Eastern, Middle 

and Western States 192 

Draining after scrubbing 9b 

Drum wheel handler • - • • • ■ • • < u 

Dry hides, table showing cost ot tan " 

xiiii°" £&& 

Drving inthe turret dryer 97 

saving in time and labor and im- 
proved color made ill 

size of building necessary. .. . . ..113 

how steam should be admitted. .113 

openings for light and air 113 

i levator for raising the leather, .llo 
influence of light and heat. . . . . .115 

conveying leather from the 
van! to the drying lofts 136 



Gambier, or terra japonica . . . .... . 162 

its use as a substitute for bark. . .164 
Gallic acid, sole leather raised by . . 80 

German fiesher, the ^ 

German sole leather. .............. ^ 

Glue stock, saving and caring for the. 149 

Grain and buff leather. • ^ iu 

difference between that made 
from tanned leather and that 

made from green hide 211 

stamping *]% 

strength of ■•• ■• ■*" 

suggestions for manufacture ot. .iV6 

Grain, nature of the • • • ■ -M* 

great care necessary to make it 

perfect •-. ; lui 

English custom of striking out 

the .■••108 

Grate surface necessary in wet tan 

ovens ••_ lli 

Grease on hides to be removed by an 

alkali ' 

how to purifv and cleanse. ..... „219 

table showing cost ot 



Green hides, table showing cosx oi 

tanning • lAA 



H 

Hair, cattle and calves', saving the. .150 
cleansing and preparing for mar- 
ket l f 

Handling ••••••• aq *<K2 

the hand reel. 69, 2o2 

the rocker handler o»> z^ 

the drum wheel handler /" 

a method of raising packs a 

tub wheel handler f* 

the " England " wheel £* 

mechanical power '* 



INDEX. 



303 



Handling— The " Cox'' rollers 71 

on frames. 75 

vise of acid in 76 

for upper and harness leather. . . 83 

Hand reel, the 69 

Hanging hides in sweats 27 

Heating liquors, pan for 260 

Heating surface necessary in wet tan 

ovens 228 

Hemlock bark, a fair colored leather 

from 56,101 

white and red 156 

weight of a cord of different 

kinds of 156 

growth of in different sections of 

country 158 

Hemlock leather made to imitate oak 

leather 107 

Hides, selection and classification. ... 17 
assorting at each stage of the tan- 
ning process 17 

softening in soak and mill 18 

breaking the nerve 19 

kinds to be worked at the same 

time 21 

sweating 23 

hanging in sweat pits 27 

liming 31 

bating 33 

trimming before tanning 43 

skinning" the cheeks and throats. 44 

handling and plumping. 76 

laying away 8-A 

experiment with N. Y. City 85 

cells of filled with water and not 

air 178 

species and growth of 188 

healthy and well grown 188 

differences in at various seasons. 189 
climate and food, effect of on. . . . 189 

Hide mill, the 250 

Hide worker, Henry Lampert's 282 

Hook marks 91 

Howard leather washer, the 95, 264 

How much leather will a cord of bark 

make 160 

Hydrostatic pressure, experiment in 

tanning by. 177 

I 

Improved breeds of cattle make hides 

thin and spready 190 

Instantaneous combination of tannin 
with gelatine 92 

Insurance, old and new rates for tan- 
neries 138 



Knocdercr's vacuum tanning process. 181 
Korn, Charles', whitcner 276 



Laying away, time required for sole 

leather 84 

gives better color than handling. 85 



Laying away as practised in Europe. . 86 

in Great Britain ' 

weight of liquors on last layer . . . 88 

grain or flesh up * HI 

Leaches, round or square 12fi 

construction of L2S 

capacity of to he proportioned to 

tannery 122 

brick and cement for in England. 133 

Leaching 55 

proper degree of heat to be used. 57 

the double leach 58 

the press leach 58 

how it is worked 59 

loam packing for 60, 119 

construction of 61 

operation of. 62 

number of times bark is 

washed with 64 

the Allen & Warren leach 65, 260 

concentrated liquors obtained by. 66 

the McKenzie leach . . 66 

revolving leach 67 

Leather interest of the United States 
according to the census report 

of 1870 245 

Leather should be dry when stuffed. .222 

Leather splitter, the Union 282 

Liming after sweating 28 

when vitriol is used 29 

to unhair 31 

kind of lime to use : 31 

preparation of the limes 31 

old limes 32 

time required for 32 

Prof. Liukin's process 34 

the '-Buffalo " method. 35 

handling in limes 36 

Liquors, feeding hides with Btrong. . 82 
Loam foundation desirable for tan- 
neries . L19 

Loam packing for leaches 60 

Location of tanneries 118 

placing the buildings to reduce 

fire risks 137 

Loss of tannin hi making leather 173 

M 

Milling after, sweating 28 

Morocco vs. "pebble grain" leather.. 212 
Myrabolams L6G 

N 

Nerve, breaking of tho, in hid. a and 

skins 19, 40, 197 

O 

Oak bark 159 

the rock oak, white oak, and it. I 

oak l'ii 

gro-H 'ii "i' < •: i K trees 161 

Oiling before drying 97 

(Md liquors, arid in 

One story buildings best fur tan- 
neries L34 



304 



INDEX. 



Palm oil used bv European curriers. .207 

Patents for tanning inventions 176 

Paste ^l 

Press leach, the «» 

" Puddling in" the vats 1A> 

Q 

Quick tanning process 176 

R 

Reel for handling leather 69, 252 

Refuse of tanneries— Utilization ot. .14b 

Rocker handler, the 69, 25o 

Rollers for handlers •• • • • • • 74 

Rolhng, proper condition of the lea- 

ther for 98 

effect of the first 99 

a second rolling necessary. . - 9 

the American leather roller 256 

Rossing hark • • 141 

difficulty of separating the ross. .142 
will it pay to ross bark for ex- 
port?.' 1*4 

•'Rounding" ............... 48 

Russia Leather, original color ot lUb 



S 



8 



Safety coupling for a bark mill 49 

curing— the Lockwood scourer 2b8 

the Fitzhenry scourer 270 

the Burdon scourer 272 

Screen for ground bark 50 

Setting the vats and leaches 120 

Sheepskins, effect of vitriol on 79 

Skins— Breaking of the nerve in 

French an 1 German calfskins. 20 

Selection before tanning 20 

Liming 34 

Fine texture of French, German 

and S-!< ibs calfskins 193 

Size paste 221 

Soap blacking ■*«! 

Soda ash, with lime, for unhairmg. . . 3o 
Soda ash or sal soda for removing 

white spots ?1 



24 
24 

25 



.Sumac baths for making a fair color. 101 

Sweating, in Europe 23 

by steam 

construction of cold sweat pits, 
to control the temperature of the 

pits 

grease and salt on hides, stop- 
ping the action 'of the sweat- 
in-- process 29 

improved sweat pits , ~-< s 

" Sweet fern" 1Gb 

T 

Tan burning ; - --47, 224 

the first practical success m 147 

Tanneries, construction of. 

Leaches 

Framework and iocation of build- 

in^s ■ loi 

The turret dryer Ill 

Plans, foundations, etc 11 < 

Tannin, difficulty of separating from 

extractive matter -55 

instantaneous combination of 

with gelatine 92 

Tanning materials 135 

Tanning, the cost of 1|><J 

in Europe 174 

Tan press, the Salem. 

Tawing hides and skins 



..186 



26 
33 

35 



18 
156 

80 
210 

65 



Temperature of sweat pits 

of water in wheeling lime 1 hides. 

of limes ■ •■• -■ 

of water for leaching with the 

press leach 57 

of the staffing wheel 219 

Time of tanning by Knoederer's vac- 
uum process 183 

Tools for tanners and curriers 286 

Transferring packs, a method of 71 

" Trim" of leather adopted by Eng- 
lish tanners • • • 42 

Trimming of hides 43, 28* 

Tub wheel handler, the - • 72 

Turret dryer, the HO, 2o * 



137 



Softening hide 

Soil and climate, effect of on bark 

Sole leather. German 

Splitting machine, the 

Sprinkler leach, the 

Steam power to be conveyed by steam 
in pipes rather than by shaft- 
ing 

Streams, "manufacturing" and "cu- 
linary" H8 

Strength of liquors for handling 83 

f. tr lay ing away 84 

for last layer 88 

Stuffing wheel, the 27 

: l . 1 and sulphuric acid for 

bleaching leather 100 

Sulphur, with lime and soda ash, for 

unhairing 35 



U 

Union whitener and buffing machine. 

the O0 

Union leather splitter, the 282 

Upper leather tanned by a cord of 

bark 



278 



170 



Vacuum tanning • • • 177 

leather made " baggy "by 182 

Valonia •••• ] { ' t ' 

V its to rest on the log conductors.. .121 

-Buffalo," J21 

box 1-- 

Vegetable oils for currying -i07 

Vitriol, the use of lime on hides raised 

by 28 

its use in Great Britain 49 

its employment in handling 7b 



305 



INDEX. 



Vitriol — Difficulty in determining 

. how much to use 78 

should not be used on sweat 
stock 79 

W 

Warm water to be used in soaking 

hard hides 18 

Washing after coming from the laya- 

ways ". . . 94 



Water in cells of hides 178 

Wheel scrubbing 95 

Wheel stuffing 219 

Whitener, Charles Korn's 27G 

tbe Union 278 

Fisk's 280 

White spots in sole leather 89 

Wilcox, Pa., cost of wet tan furnace 

at 210 

Working hides and skins to break the 

nerve 40 



APPENDIX. 



REPORT 



OP 



THEEON SKEEL, C. E., 



ON THE 



COMPARATIVE ECONOM IES 



OF 



BUENING WET SPENT TAN 

BY 

THE VARIOUS DETACHED FURNACES NOW IN USE 

BY THE TANNERS OF PENNSYLVANIA 

AND NEW YORK, 



NKW YORK : 

OFFICE OF THE SHOE AND LEATHER REPORTER. 

17 Spruck Strkkt. 

187G. 



& 



<m 




BURNING WET TAN IN DETACHED FURNACES. 

In order to explain and justify the great particularity with which this series of experi- 
ments have been conducted, it is proper to say that in the suit of Black vs. ihorne, in 
which was involved the merits of the so-called Thompson patent for burning wet tan 
bark, saw dust, &c, both Profs. Silliman and Thutston insisted upon the theoretical 
and practical superiority of the Thompson furnace over tbose in public use at the time 
of this patent. Prof. Thurston was compelled to admit, however, that methods outside 
of the Thompson patent were quite successful, and gave practically all tho power re- 
quired, but thought, from his observation and experiments at two tanneries, that the 
Thompson furnace would give about thirty per cent, better results from a given amount 
of wet spent tan than the furnaces outside of the patent. 

As this result was known by all practical tanners not to be true, they naturally felt 
anxious to have the experiments made with more care than Prof. Thurston had pre- 
tended to exercise. He guessed and estimated too much, and weighed and measured 
too little, to carry the conviction of his theories, as against the known results in actual 
practice. Hence it was that J. B. Hoyt and J. S. Schultz, representing the tanners, 
sought for some expert that should carefully retry the experiments so imperfectly per- 
formed by Prof. Thurston, and they were greatly aided in this endeavor by Mr. B. F. 
Isherwood, Chief Engineer of the U. S. Navy. The letter received from him so fully sets 
forth the grounds of his commendation that it is here inserted with the correspondence 
and report which follows. 



New York, August 17, 1875, 111 East 36th Street. 

Deae Sie : — I take the liberty to write you in regard to some experiments which I 
understand you contemplate, and which I hope you will have mad<>, on the evaporative 
efficiency of wet tan bark burned in the furnace of a steam boiler. The subject is one 
of great interest in engineering, which is my apology for thus troubling you; and the 
problem should be solved in so complete and appropriate a manner as to remove for- 
ever the doubts now resting on it. 

In my opinion there is no person of my acquaintance so thoroughly qualified to con- 
duct such experiments, and ascertain their result^, as Mr. Theron Skeel. He has all 
the necessary qualifications of an education, both mathematical and practical, and he is 
an expert experimentalist. He is thoroughly versed in the subject, and his reoort will 
command a respect and confidence not easy to obtain for that or any other. 'Whatever 
experiments Mr. Skeel makes will be devised in a manner to defy hypercriticism as to 
the propriety of their results, and his literary ability will enable bJm to present them 
so clearly, forcibly and full that they will be understood and accepted by all. 

Should you conclude to have these experiments made, I volunteer the advice that you 
allow Mr. Skeel to have full power in devising and conducting them. By so doing I am 
confident you will obtain such results, and in such a manner, as will forever settle the 
questions at issue. The worst extravagance will be to so limit the experiments as to cause 
the least shadow of doubt to remain. I hope, in the interest of industrial science, that 
you will furnish Mr. Skeel the means to do justice to both himself and the subject. 
Your obedient servant, B. F. ISHERWOOD, 

Jackson S. Schultz. Chief Engineer U. S. Navy. 



New Yoek, Aug. 20, 1875. 
Me. Thebon Skeel: 

My Bear Sir: — Within a few days I have received a letter from B. F. Isherwood, Esq., 
Chief Engineer of the U. S. Navy, in which he recommends you as a suitable person 
to test the evaporating power of wet tan bark when burned in furnaces in the front of 
steam boilers. 

In view of your conceded ability, in common with other tanners who are interested * 

in the subject above referred to, and particularly as developed by the controversy 

arising out of the suit now pending on the Thompson patent for burning wet fuels, we 

desire that you at once proceed to test, by a series of experiments at several tanneries, 

the comparative merits of the various methods, but p rticularly those of Thompson, 

Hoyt, Crockett, and other such modifications of these as in your judgment may tend to 

throw light upon the general subject embraced in the "consumption of wet fuels in 

detached furnaces or ovens." 

#* * * ******* 

Our wish and instructions to you are, that you make your tests in the most thorough 
manner, and, when you have finished your work, that you report to us in writing. 

Very truly, 
(Signed) J. S. SCHULTZ, on beh. If of J. B. Hoyt and others. 




REPORT. 



86 Irving Place, New York, Dec. :>0, 1ST-"). 
Jackson S. Schultz, Esq., Nos. 63 and 65 Cliff Sired, New York, 
J. B. Hoyt, Esq., arid others : 

Gentlemen — I submit the following report of the experiments 
made in accordance with your letter of instructions preceding. 

The experiments were made on three forms of furnaces de- 
signed to burn spent tan in the condition in which it comes from 
the leaches. The object of the experiments was to determine in 
which kind of furnace the hot gas developed by the burning of a 
given quantity of wet tan would evaporate the most water in the 
boilers attached. The furnace which excels in this resped may 
be said to be the most economical of bark. 

This must be distinguished from commercial economy, which 
depends upon the value in money of the spent tan, the cost of 
the furnace and of attendance and repairs. In the present state 
of the art about one-half of the spent tan is thrown away in all 
sole leather tanneries, for they only use about one-half of all the 
tan made to make the steam necessary for the whole tannery. 
Under these circumstances the moiety of the tan has no value in 
any case, and in some locations is worse than valueless, for 
the tanners are prohibited by law from dumping the tan into the 
stream, or where there is no stream to dump it into (as is some- 
times the case), they are obliged to either ca rl it aw ay orto ered 
an additional furnace especially to burn it. The term economy 
as used in this paper refers to economy in the use of bark <»>h/. 

The economy of any furnace (the term furnace including the 





whole combination of ovens and boil3rs) evidently depends 
upon : 

1. The total heat which would be developed by the perfect 
combustion of the quantity of tan fed into the oven. 

2. The portion of the heat that is developed by the combus- 
tion that takes place in the furnace. 

3. The portion of the heat developed which is utilized by the 
boilers. 

The first condition depends entirely upon the bark, and is in- 
dependent of the oven or boiler.* The second condition depends 
almost entirely upon the oven and is independent of the boiler. 
The third condition depends both upon the furnace and boiler. 

In order that any set of experiments should be conclusive in 
themselves without reference to any conditions but the quantity 
of tan burned and of water evaporated, it is necessary that a set 
of ovens should be built of each kind and connected to exactly 
similar boilers, and that these ovens shall be fed at the same 
time with the same quantity of tan from the same leach, and that 
the pressure of steam and the temperature of the feed water 
shall be the same in each case. Such experiments would be 
comparative, but are not practicable. In the absence of exactly 
similar conditions, it is necessary to consider (so far as we are 
able) all the variations. 

The experiments described in this report were made in 1875 
as follows : 

Sept. 22 — Crockett furnace, Stevens' tannery, Great Bend, N. Y. 

Sept. 24— Crockett furnace, Wells' " Southport " tannery, Webb's Mills, N. Y. 

Sept. 26 — Thompson furnace, H. F. Inderlied, Brackneyville, N. Y. 

Sept. 29 — Thompson furnace, Weed's tannery, Binghamton, N. Y. 

Oct. 6— Crockett furnace, Wells' " Southport " tannery, Webb's Mills, N. Y. 

Oct. 16-17— Hoyt's furnace, Wilcox Tanmug Co., Wilcox, Pa. 

Dec. 9— Crockett furnace, Wells' "Southport " tannery, Webb's Mills, N. Y. 

Dec. 10— Crockett furnace, Wells' " Southport " tannery, Webb's Mills, N. Y. 

The plans and dimensions of the ovens and boilers and the 
detailed description of the experiments are given in the appen- 
dices to this report. 

FUEL. 

The fuel was in all cases spent bark of hemlock trees, called 
" tan." The trees are felled while living and stripped of their 
bark during the summer season. The bark is piled up in the 

•If the tan were so thoroughly leached and dried as to be fed into the furnace nearly 
in the condition of perfectly dry wood it is probable that the combustion would be more 
nearly perfect, with the same supply of air, than if the same furnace were fed with im- 
perfectly leached bark. 



\ 




b L_ 

woods after being stripped, and during the winter hauled into 
the tannery and piled up again until needed for use. 

The bark is peeled from all sizes of hemlock trees down to about 
6 inches in diameter, the largest being about 30 and the average 
perhaps 15 in diameter. Good average hemlock land will peel 
about 12 cords of bark to the acre. One man will fill, peel and 
pile about 1^ cords of bark per day. 

The bark when originally peeled from the trees, at the same 
season, has probably nearly the same composition in all locali- 
ties. This has been found to be true of wood, and therefore 
inferentially of bark. In that condition, then, a given weight of 
bark would probably correspond to a given quantity of heat in 
all cases. If, however, it is not burned at once, it dries more or 
less according to the length of time and the circumstances under 
which it is stored. The time of storing varies in practice from a 
few weeks to several years, and while sometimes it is stored in 
large piles and exposed to the weather, at others it is stored in 
small piles under sheds. After being stored a certain length 
of time it loses all the water except about 14 to 16 per 
cent., leaving the balance containing 84 to 86 parts of 
dry wood and 14 to 16 parts of water." If more thor- 
oughly dried than this by exposure in a hot kiln, it will on 
exposure to the atmosphere reabsoib an amount of water vary- 
ing from 14 to 16 per cent, with the hygrometric condition of 
the air. Dry wood, in the sense used in this paper, is under- 
stood to be wood that has parted with all the water it will when 
exposed to dry air at a temperature of 110° Centigrade or 230 
Fahrenheit. 

The unit of measure of the bark in this condition (before 
being ground,) called " chip bark," is among tanners the cord, 
being a pile of bark 8 feet Jong by 4 feet wide by 1 feel high. 
The weight of this volume of bark is variously estimated at 
from 1,800 to 2,240 pounds, and probably varies within these 
limits with the manner of packing and the weight of water 
contained. 

Before leaching the bark is ground in a machine called a '" barb 
mill." The bark in its original condition consists of an outer 
shell of hard dry substance, analogous to " cork," and an ii 




*I am informed by a gentleman who has bad considerable I spi ri< n< 8 In drj I H 
for manufacture into spools that Rreen wood if cut into fagffotfl and i q 0* dto I 
in sheds protected from the weather, would lose in ..nr v.-ar all ib.-wm.-r il contained 
except about 15 per cent., as compared with lain dried wood fc< 150 di f. 1. I bo kiln 
dried wood would reabsorb this 15 per cent, when exposed to the air. 

> 





layer of a substance containing more sap and more like woody 
fiber. In the first process of grinding the outer shell grinds 
much finer than the inner. In some tanneries the whole product 
from the mill is sifted in a revolving screen, and the coarser part, 
consisting mainly of the large pieces from the inner layer, is sent 
back to the mill and reground. 

The weight of a cord of ground unleached tan (being deter- 
mined by weighing the contents of several boxes containing 
exactly 25 cubic feet each) the bark being shoveled into the 
box, not packed, and struck off with a straight edge, was found 
to be at the various tanneries as follows : 

Wells' 2,582 pounds 

Brackneyville 2,353 pounds 

Wilcox (fine) 2,418 pounds 

Wilcox (coarse) 2.284 pounds 

Average 2,351 pounds 

The water contained in the last two specimens as compared 
with the same dried at 110° C. was found to be : 

Wilcox (fine) 18.1 per cent 

Wikox (coarse) 17.0 pei cent 

And therefore the weight of a cord of dry ground unleached 
bark : 

Wilcox (fine) 1,980 pounds 

Wilcox (coarse) 1,895 pounds 

Average 1,938 pounds 

But at Wilcox all coarse ground tan is sent back to the mill 
and reground, and therefore the weight of a cord of fresh ground 
bark will be the mean of the coarse and the fine, or 2,418 
pounds, the percentage of water contained 17J, and the weight 
of the cord of dry bark 1,995 pounds. 

Probably no sensible error will arise if we assume for all cases 
the weight of a 

Cord of dry unleached ground bark = 2,000 pounds. 

In this condition probably the same weight of bark will de- 
velop the same amount of heat in all localities, and within the 
limits of practice the same is true of equal volumes. 

After being ground the bark is "leached," that is, placed in a 
wooden leach having a perforated bottom and saturated with warm 
water for several days. This water percolates through the bark 
and carries off with it, if the process is continued long enough, 
all soluble matter. 

After the soluble matter is supposed to be all out, the water 
is allowed to drain off and the residue, called " wet spent tan," 






is shoveled out of the leaches and carried to the furnace to be 
burned. 

A cord of the bark in this condition has been in former experi- 
ments taken as a unit of measure of the amount of heat equiva- 
lent to the tan fed into the furnace. In order to test the 
accuracy of this assumption the whole quantity of tan burned in 
each experiment was measured and weighed, as in case of dry 
bark, by shoveling it into a box containing about | cord, striking 
off with a straight edge, and weighing the contents. 

The weight of a cord of wet leached tan under these circum- 
stances was found to be at various tanneries as follows : 

Stevens' 4,442 pounds 

Wells' (I) 4,294 pounds 

Wells' (3) 4 ; 275 pounds 

Weed's 4 270 pounds 

Wells' (4) 4 : 260 pounds 

Wells' (2) 4,225 pounds 

Brackneyvilie 4,112 pounds 

Wilcox 4,07G pounds 

Average 4.244 pounds 

The per centage of water lost by drying* at 110 C. was found 
to be at the various tanneries : 

Wells' G3.4 

Wells' (2) 62.8 

Wells' (4; 62.3 

Wells' (3) 61.5 

Stevens' 61.6 

Wilcox 61.2 

Brackneyville 59.0 

Weed's 55.1 

*The average composition of bark dried at 80 deg. C. is given by M. Violet ; 

Carbon 48.6 

Hydrogen 6.3 

Oxygen 41.8 

Asb 8.3 

100 
If tbis bark had been dried at 110 deg. C, as was done in the experimentn, it * i (imposi- 
tion would have been changed by the loss of 5 per cent, of water, and would have 1 •>■■ D 

Carbon 51.9 

Hydrogen 7.0 

Oxygen 89.8 

Ash 3.5 

100 
Or of 51.2 per cent, carbon, 1.2 per cent, hydrogen. 44.2 per cent, of hydrogen aud 

oxygen in the proportion to form water, and 3.5 per cent. ash. 

The weight of the water which one pound of the bark in this condition would < H 
rate from 212 deg. ¥., computed by allowing 15 pounds pet pound ofotrbofl and r * 
pounds per pound of hydrogen, will be : 

Carbon 51.2@15 = 7.68 

Hydrogen 1.2@G4 = 0.77 



8.45 
Of this 55-100 of pound of water are latent in gas, leaving avadaldo heat 7 9-10 



# 



*<& 




And consequently the weight of the dry portion of the cord : 

Weed's 1,917 

Wilcox 1,582 

Wells' (4) 1,606 

Wells' 03) 1,646 

Brackneyville 1,686 

Stevens' 1,710 

Wells' (1) 1,572 

Wells' (2) 1.572 

Average 1,661 

Average weight, rejecting Weed's 1,625 

In order to try the effect of packing on the weight of the cord, 
several boxes were weighed containing tan packed by a man 
(weighing at Wells' about 150 pounds, and at Brackneyville 180 
pounds) stamping it down as fast as shoveled in, the top being 
struck ©ff with a straight edge as before. The weight of the cord 
was as follows : 

Wells' 5,327 

Brackneyville 5,490 

Average 5,405 

The per cent, of water contained being as before, the weight 
of the dry portion will be : 

Wells' 1,950 

Brackneyville '. ." 2,251 

Average 2,100 

At "Wilcox the whole contents of two leaches were weighed. 
The weight of a cord at the density of packing in the leach was 
found to be : 

Wilcox 5,219 

And the weight of the dry portion : 

Wilcox 2,025 

In the experiment marked Wells' (3) and Wells' (4), the tan 
was used during the first part of the day from the bottom of one 
leach and during the second part from the top of another. The 
following exhibits the weight of a cord taken from various parts 

pounds from 212 deg. Probably no sensible error will arise if the thermal equivalent of 
one pound of bark dried at 110 deg. C. is taken at 8% pounds of water evaporated from 
212 deg. F. 

The thermal equivalent oJ a coid should 1 e in water evapoiatcd from 212 deg : 

2,000X8.5=17 000 pounds. 

Prof. Jobnson has made some experiments on dry pine wood giving 7% pounds of 
water from 212 deg. F. No estimate of Ibe water contained is given, but assuming it to 
have been 20 per cent, (and it could not have been less), there results from his ex- 
periment : 

Pounds of water evaporated from 212 deg. F. by pound of pine wood (dry) 9.36 

In his experiment, 1 36-100 pound of water were latent in gas, leaving available 
heat, 8.02. 




of the leacli, the whole capacity being 10 cords, the bottom cord 
being called the 10th : 

1st day, 8th cord in leach, 48 houra draining, weight 4.262 pounds 

1st day, lObh cord in leach, 56 hours draining, weight 4,306 pounds 

2d day, 1st cord in leach, 24 hours draining, weight 4,262 pounds 

2d day, 2d cord in leach, 32 houra draining, weight 4,211 pounds 

2d day, 3d cord in leach, 38 hours draining, weight 4 257 pounds 

2d day, 4th cord in leach, 44 hours draining, weight 4,200 pounds 

A sample of bark to determine water was not kept separately 
for each cord. The weight of a wet cord seems steadily to increase 
from the top toward the bottom, but not very rapidly, the whole 
increase being less than 2 per cent. The masses of bark were 
broken up by shoveling out of the leach, and were all measured 
at the same density, these figures having no reference to the 
tightness of packing iu various parts of the leach. 

The extreme variations of weight of the dry portions, from 
1,917 at Weed's to 1,572 at Wells', would at first seem to point 
to an error in measurement. The following exhibits the 
difference : 

Wells'. Weed's. 

■Weight of cord of wet tan 4,294 4.270 

Weight of dry portion 1,572 1,917— difference 345, Weed's most 

Water 2,722 2,353— difference 369, Welles' most 

*The dry green bark, having the same composition in both 
cases, is, according to M. Yiolet, made up of : 

1. Of a material called cellulose, which has always the same 
composition. 

2. Of an incrusting material which is richer in carbon and 
hydrogen, and of which the principal constituents are. resin, 
gum, starch, sugar, glucose and tannin. 

3. Of mineral matter or ash. 

The soluble constituents are wholly or partially extracted, 
according as the process of leaching is more or Less complete. 
It is possible, then, that the soluble portion was nearly all ex- 
tracted from the Wells' bark and but partially extracted Erom 
the Weed's bark, the pores being filled with water in both cases, 
but there being more empty pores to contain water in Welles' 
bark. 

If this should be true, the balance of tbe soluble matter I 
be extracted by thorough leaching, and the dry portion remain- 
ing should have been nearly the same weight iu every ease. 

In order to test this theory a given weight of wet bark was 
taken, the sample from each tannery boiled for lU 1 1 < >urs, the 



T& 



♦Annales de Chimin and de Physique, vols. xxiii. and xxr.n. 

: $<§ 







1» 



liquor filtered, and the balance dried at 110° C. as before, 
result of this experiment was as follows : 



The 



Original weight of 

dry cord from 

leach. 

Stevens 1,710 p junds 

Brackney ville 1,619 pounds 

Weed's 1,917 pounds 

Wells' (1) 1,572 pounds 

Wilcox 1,582 pounds 

Wells' (2) 1,572 pounds 



Loss of weight hy 
boiling 2% 
hours. 
84 pounds 
113 pounds 
403 pounds 
93 pounds 
98 pounds 
148 pounds 

157 



Final weight of 
leached dry 
cord. 

1,626 pounds 

1,536 pounds 

1,509 pounds 

1.479 pounds 

1 484 pounds 

1,424 pouuds 

1,510 



Average 1,667 

The variations of the weight of the dry boiled portion may be 
due in part to the fact that the soluble matter is not yet all out, 
for they were only all boiled the same time, and not until they 
ceased to lose, as would have been the final test. Enough, how- 
ever, was done to show that so far as the extremes are concerned, 
Weed and Wilcox, the measurements are probably correct. 

A specimen of the unleached bark from Wilcox's was soaked 
in cold water for 36 hours and boiled for 6 hours, the liquor 
filtered, and the residue dried at 110° C. as before : 

Original weight of Loss of w. ight Final weight of 
cord dry un- 
leached bark. 

Wilcox (fine) 1.980 

Wilcox (coarse) 1,895 



by leaching 


cord boiled 


and boi iug. 


dry bark. 


341 


1,639 


366 


1,529 


354 


1,589 


365 


1,630 



Average 1,937 

Screened and reground bark at Wilcox 1,995 

This bark would probably have lost more if the process of 
leaching had been continued for six days, as in practice, in place 
of 42 hours. 

Probably no sensible error will arise if the weight of a cord of 
thoroughly leached bark from the tannery be taken at 1,400 
pounds, when dried at 110° C. 

It appears, then, from these experiments that the average 
weights are as follows ; 



Cord of average green 
ground bark. 

Soluble matter 500 pounds 20 per cent 

Insoluble matter 1,500 pounds 60 per cent 

Water 500 pounds 20 per cent 



Cord of well leached wet 
bark from tannery. 

000 pouuds 00. per cent 

1,500 pounds 35.7 per cent 

2,700 pouuds 64.3 per cent 




2,500 pounds 100 per cent 4,200 pounds 100 per cent 

The experiments do not show what the 500 pounds of extract- 
ive matter consists of, but only that it is material soluble in hot 
and cold water. 

The proportion of water does not increase with the size of the 
lumps, as was found by drying a specimen of very large lumps 



II 



from cord. The water contained was shown to be exactly the 
same as in the fine. 

A cord of tan thoroughly leached and saturated with water 
weighs more and contains more water than a cord imperfectly 
leached.* 

A cord of fine ground tan weighs more than a cord of coarse 
ground, as a barrel of meal weighs more than a barrel of corn. 

THE CROCKETT FURNACE. 

The Crockett furnaces experimented upon consist of an oven 
of fire brick, constructed near the boiler, and having a set of 
cone grate bars of cast iron. The tan is fed in through doors iu 
the front. 

The depth of the furnace is limited, as in the ordinary furnace 
for coal, by the distance to which the fireman can easily throw 
the tan, to 6| feet, but may be as wide as is necessary 
to give the grate surface, and varies in practice from G to 12 
feet in width. 

The fire is started (as in every case) with dry wood, and con- 
tinually replenished until the brick work is hot, after which no 
more wood is necessary. The frequency of feeding depends 
upon the rapidity of consumption. When burning at the rate of 
7 pounds of dry tan per square foot of grate per hour, each por- 
tion of the furnace requires to be fed with fresh tan every three- 
quarters of an hour at least. If there are several doors, each d< >or 
has to be opened every three-quarters of an hour. At Welles 1 
furnace there were three doors, and some door was opened every 
15 minutes. The time of feeding under these circumstances was 
about 1^ minutes, so that the doors were open one-tenth of the 
time. If the fuel burned regularly over the grate, the feeding 
could be less frequent. 

The crown of the furnace is a segmental or elliptical arch, and 
the distance from the crown to the grate varies from I! bo - '. 
feet in different ovens. The fire bridge is at the back of 1 1 1 « - 
grate, and is a continuation of the back vertical wall of the ash 




*The specific gravity of the material extracted from the bark in nearly l 1 , timet that 

of water, so that the 500 poundB of material extracted would be replaced by SM poundl 

of water. The weight would be as follows: 

Hi-furi leaching After l.aclung 

Soluble matter 500 

Solid matter 1,800 

Water mechanically held between particles 2.250 

Water in pores originally filled with soluble matter 

Weight of cord of wet tan 4,3 

These are nearly the weights of cord at Wilcox and Weed's. 






•&- 



iX± 




13 



pit. It rises about 1^ feet above the grate, and extends entirely 
across the oven. The arch over the oven is generally from 2 to 3 
feet longer than the grate, and forms the support for the front 
end of the boilers. 

The boilers are generally horizontal flue boilers, with two flues ; 
the products of combustion after leaving the furnace, passing 
forward under the boilers, returning through the flues, and finally 
passing in front to the chimney through a sheet iron connection. 
The chimney is generally of sheet iron, and is sometimes set 
directly over the boilers, and sometimes carried on a brick 
foundation. 

The main difficulty in keeping a uniform fire is the compara- 
tively small weight of fuel in the furnace at one time. If the 
fire is carried on an average 9 inches thick, there will only be in 
the furnace at one time (if the grate is 6^ feet long by 12 feet 
wide) 800 pounds of combustible. At the rapid rate these fur- 
naces are generally fired, being, in the case of Wells' (1), 800 
pounds dry tan per hour, this would only last one hour. A fur- 
nace burning coal at the rate of 10 pounds per square foot per 
hour would contain coal enough to last 6 hours. The conditions 
of a tan bark fire, then, in the Crockett furnace, fed every hour, 
may be imagined by supposing a coal fire fed every six hours. 

STEVENS' FUKNACE AT GKEAT BEND. 

The performance of this furnace during the experiment indi- 
cates the economy of the Crockett furnace when forced to the 
utmost. During the experiment the number of pounds of dry 
tan burned per hour was : 

Per square foot of grate surface 10.70 

Per square foot of heating surface 1.61 

Per square foot of the cross area of flues 258 00 

In order to consume this tan the damper and ash pit doors 
were kept wide open and the furnace fired every ten minutes. 

The method of firing was first to fill the holes that had burned 
through, and then to cover the whole surface with a layer of tan 
about 3 inches thick. 

The tan thrown in first forms a uniform layer over the surface. 
It appears to undergo a species of distillation, during which the 
water is evaporated, the tan maintaining its original brown color. 

Just before firing, the furnace was a dull red over about half its 
surface, the color fading out into a black toward the front, and the 
surface of the tan was burned through into holes wherever the origi- 
nal tan was thinnest or the fire hottest, but mostly where the grate 
had broken away and left large crevasses through which the tan fell 



B* <§0 

f . -^, 

into the ash pit. At the instant before firing, the temperature of 
the gases leaving the furnace was scarcely sufficient to melt silver, 
and there was no smoke coming from the chimney, but occasion- 
ally a few sparks. 

The fireman would now throw in as described the charge of 
about 300 pounds of wet tan through both doors alternately. 

Immediately on closing the doors the destructive distillation of 
the tan commenced, under the combined influence of the heat 
radiated from the surface of the arch above and of the hot embers 
on the grate beneath. By looking in through some of the crevasses 
in the front of the furnace hundreds of little jets of white smoke 
could be' seen issuing from the whole surface of the tan. 

During the process of distillation, which lasted about 3 ininut« 3, 
the smoke and steam which was unable to find an outlet into the 
chimney issued in small quantities through the crevasses in the 
brick work into the fire room, or was forced back through the grate 
into tbe ash pit. A careful examination of the edges of the 
crevasses in the brick work showed them to be covered with a 
deposit of an oily substance, undoubtedly condensed from the 
smoke, showing that at this time the combustion was imperfect, 
and that the smoke issuing from them had contained combustible 
matter. During the process of most rapid distillation, no air 
entering the ash pit, combustion must have been entir> ly suspt nded, 
and whatever gases were generated must have passed away un- 
consumed. Toward the end the crown of the furnace becomes 
black all over, owing no doubt to the heat absorbed by the water 
in the tan. 

Now there are signs of combustion commencing. These are, 
first, the cessation of the smoke from the crevasses into the fire- 
room, and little jets of yellow flame replacing the smoke in the 
furnace. They begin gradually, and in about two minutes cover 
the whole surface of the tan, which gradually grows red bo< and 
consumes. From the time of the first appearance of the flame, 
the crown of the furnace gradually grows hotter, and just before 
firing is red hot over half its surface as before. 

The appearance of the smoke during the firsl pari of the cycle 
indicates the presence of combustible gas at thai time. I ufortu- 
nately, the loss of heat by combustible gas does nol ceaa when 
the flame commences, for although at that time some of the gas is 
consumed, probably a large part «>f it, forced from the tan by the 
heat of the embers below, and issuing into B comparative^ OOol 
oven, does not acquire sufficient temperature to consume, even 

$?& #<& 




11 




though mixed with sufficient air. I consider that in the Stevens 
furnace, fired in this way, probably the whole effect of the gaseous 
portion of the fuel (about 25 per cent.) was lost. 

This loss was aggravated by the very thin layer in which the 
bark w r as spread over the whole surface, allowing all the water to 
be evaporated in a few minutes, the volume of gas completely 
filling all egress from the boilers, thus arresting combustion and 
allowing the furnace to cool down below the temperature necessary 
for the ignition of the gases expelled during the subsequent 
process. 

This loss would have been probably almost entirely prevented 
by closing the ash pit down so as to burn about half as much tan, 
or by putting in two more boilers, so as to have twice as much 
area of flue. In either case the effect would be to give an excess 
of area to the outlet over the inlet of the oven, so that the com- 
bustion need not cease wiiile the distillation is taking place, in 
which case the temperature of the oven would be maintained 
nearly constant, and the gas consumed as fast as expelled. 

It is also necessary for the combustion of the gas that there 
should be supplied an amount of air that does not pass through 
the incandescent tan on the grate. Unless this air is supplied the 
gas will pass off unconsumed. 

This ah' is supplied practically by the holes burned in the fire. 
The tan, after being dried in the furnace, commences to burn away 
most rapidly where tan is thinnest or the draft strongest. The 
layers of bark around this hole do not slide down and fill it, but 
stand perfectly perpendicular, or even overhang a little. These 
holes generally form on the crest of the grate bars, and in a few 
minutes enlarge rapidly, and finally lay bare the wiiole crest. 
They act a very efficient and beneficial part if not allowed to in- 
crease too much, but check the fire and cool the oven if left too 
long without being filled. 

A description of the performance of a Crockett furnace, when 
these holes w'ere in one experiment allowed to form, and in an- 
other when they w r ere kept from forming by filling up all hollow's 
with fresh tan before the surface had burned away (marked Wells' 
3 and Wells' 2), in winch it appeared that with the same rate of 
combustion, and with the same temperature in the oven, the per- 
formance of the furnace in the case wiiere the holes were kept 
open exceeded the performance when the holes were kept shut by 
more than 25 ptr cent. 

In the case of the Stevens furnace at Great Bend, the main 



15 



cause of the failure in economy was undoubtedly owing to the 

high rate of combustion at which it was forced. 

CROCKETT FURNACE AT WELLS' TANNERY. 

This furnace was similar to the Stevens furnace, except that 
there were 3 boilers, each 42 inches in diameter and 22 feet (i inch, - 
long, with two horizontal flues, 13 inches internal diameter. The 
grate was 6 feet 6 inches deep by 12 feet wide. 

The boilers had been in use for 22 years and were said to be 
covered with scales on the inside and the brick work was full of 
fissures. There were many leaks around the sheet Iron work con- 
necting the boilers with the stack and in the back connection. 

The oven was new and in good order. It had been ree< nth- 
built to replace a Thompson oven torn down, being connected 
with the same boilers. The grates were " cone grates," and were 
new and in good order. 

In the first experiment, marked " Wells' (1)," the furnace was 
tested in the cendition it was found, the rate of combustion being 
a little more than enough to supply the steam necessary to run tin- 
tannery. 

In the second experiment, marked "Wells' (2)," the air Leaks in 
stone work and sheet iron work were closed, as far as practicable, 
with mortar, and the rate of combustion was reduced 1" the same 
as at " Weed's," being nearly 64-100 pounds of dry tan per square 
foot of heating surface per hour. All the holes in the fire were 
filled, as soon as they commenced to develop, with a shov< 1 lull of 
wet tan. 

In the third experiment the same pains were taken to stop air 
leaks, same rate of combustion was maintained, only holes w< 
allowed to form in fire, and the top of the oven was covered with 
wet tan, which was afterward burned as in the furnaces fed from 
the top. 

In the fourth experiment same conditions were maintained as in 
last, except that cross section of flues were reduced to -', square 
feet. • , 

EXPERIMENT MAKKKD " WELLS (J 

The performance of the furnace during this experiment indicate - 

the effect of forcing a Crockett furnace bej 1 its capacity, the 

rate of combustion being in pounds of dry tan per hour : 

Per square foot of heating surface 

Per square foot of grate surface 

Per square foot of cross section of flu-n 

Being more than 50 per cent, in excess^f the rate m cessaij to 

allow perfect combustion. 




. 




16 




The performance was injured by the cold air which leaked into 
the flues through fissures in brick work, and particularly by the 
cold air which had leaked into the chimney by the opening in the 
sheet iron work around front connection. An opening was found 
here after experiment was concluded exposing 36 square inches. 
The temperature of the gas leaving the flues, taken in chimney 
beyond this opening, was 580°, or 270° hotter than the steam, 
while at Wilcox, at nearly the same rate of combustion, where 
there was no leak, the temperature of the gas 700°, or 380° hotter 
than the steam. The inference would be that the temperature of 
the gas at Wells' (1) would have been 680° if no cold air had 
leaked into flue between the boiler and the thermometer. The 
proportion of air necessary to reduce the temperature 100° would 
be 16§ per cent. The weight of air found in the chimney was 21 6-10 
pounds per pound of dry tan by chemical analysis, and, therefore, 
the air that passed through the flues was 18 pounds per pound of 
dry tan. 

The air passing through the fire was still less than this by an 
amount that leaked into the flues en route from the furnace to the 
chimney. 

The furnace was fed about every 10 minutes through one door 
at a time, thus making the weight of a charge about 300 pounds of 
wet tan, the balance of the hourly consumption being thrown in, 
in occasional shovel's full, to fill up holes. 

No care was taken ts fill up holes burned in fire. These were so 
large, just before feeding, as to expose about one square foot of 
opening for passage of cold air from ash pit through holes in grate 
bars. The temperature of the gases leaving the furnace, as indi- 
cated by a piece of metal on the bridge wall, was just sufficient to 
melt silver at their hottest. This occurred about midway in the 
interval of time between the feeding and the burning down of the 
fire ready to be fed again. The surface of the arch over the fur- 
nace showed at this time a bright red over about half its surface, 
fading out toward the front. As the holes developed hi the fire, 
the color died away, and was a dull red just before feeding. After 
feeding the color faded away and was invisible for a few minutes, 
gradually recovering to a bright red just before feeding again. 
The extremes of temperature of the furnace were then probably 
1,000° and 1,900°, and the average about 1,500°, corresponding to 
about 15 pounds air per pound dry tan. 

The general appearance of the furnace was as at Stevens', only 
less exaggerated. The period during which the tan was not burn- 



17 



ing was shorter, and the smoke was never returned into the fire 
room. 

The large supply of air was probably mostly due to the holes 
allowed to burn in the fire. Probably a considerable portion oi 
the combustible gas was wasted in this experiment. The heal 
unaccounted for in the gas, water and steam was 0.40 pounds ol 
water evaporated from 212°, or about 5 per cent. 

EXPERIMENT MARKED WELLS' (2). 

After the completion of the [experiment marked Wells' 1 1 I, and 
noticing the injurious effects of the holes burned in the fire, it was 
determined to try the effect of keeping the holes entire 1\ cL 
and at the same time to reduce the rate of combustion to thai at 
Weed's. 

The outside of the boiler was carefully covered with mortar to 
prevent any air leaking into the flues. The only air that did leal 
in was probably between the boilers and the chimney and had no 
effect on the economy. 

The surface of the fire was carefully watched, and as Boon as a 
hole began to develop it was closed by opening the furnace door 
and throwing as 'quickly as possible a shovel full of tan directly 
into it. 

The furnace was divided into three sections, corresponding to 
the three doors, and these sections were fired every hour, the 
weight of the charge being 400 pounds of wet tan, the balance of 
the hourly consumption being used to fill up holes. The fire was 
kept about one foot thick. The temperature of the furnace was 
higher than during the previous experiment, and nearly the same 
as in the succeeding experiment, indicating a smaller supply of air. 
As no air could reach the chamber in which the gases were gem 
rated without first passing through the 12 inches of tan. there 
could but very little free air reach them at all, and thej probabl) 
passed away entirely unconsumed, entailing a loss ifpon the tin 
nace of about 25 per cent, The steam formed was <>nl\ t! 
fourths of that in the succeeding experiment, or indicating a loss 
of 20 per cent. 

EXPERIMENT MARKED WEULS' 

The results of this experiment probably are the maximum 
this furnace in the condition which it now is. 

The rate of combustion was the same as in last experiment, and 
the air leaks were carefully stopped, except those In the sheet iron 
work between the boiler and the chimney. The furnace was 6 
about every 15 minutes, the weight of the charge being aboul 300 




tr 





18 



-<fcl 



pounds of wet tan, the balance of the hourly consumption being 
scattered in as the fire seemed to need it. 

The temperature of the furnace was more nearly uniform, being 
at the highest sufficient to easily melt silver, and at the lowest a 
dull red, or about 1,200° and 1,900°, and the mean temperature of 
not less than 1,650°. I estimated the mean temperature from the 
comparative time the highest and lowest lasted. 

The average opening of the furnace doors during the hour was 
about 7 minutes. The area exposed by the open furnace door for 
the inflow of air was about 300 square inches, while the average 
opening of the ash pit doors was about 100 square inches, or 
about one-third. It appears then that the furnace doors would 
have passed into the furnace 3 times as much air as the ash pit 
doors while they were open, but as the furnace doors would only 
be open about 7 minutes during the hour, would only admit about 
30 per cent, of the air admitted through the ash pit. The tempera- 
ture of the fire when the doors were closed being as high as in any 
furnace tested, shows that at that time the tan was burning with 
as small a supply of air as in any case, or 10 pounds per pound 
dry tan. 

The weight of air per pound of dry tan, as determined by 
velocity of smoke, was 16 pounds. A considerable portion of this 
must have leaked in through the opening in the sheet iron work. 

The temperature of the furnace is computed from heat : 

Given up by products of eombuation to steam, taking weight of air per pound 

of dry tan at 16 pounds, and adding temperature of chimney, 490 df grees 1,310° 

From the thermal equivalent of tan, allowing 0.25 pound for radiation, and 
assuming products of combustion to take all heat, the supply of air being 
16 pounds per pound dry tan 1,300" 

But the mean temperature of furnace was found to be 1,650°, 
indicating that 25 per cent, of the air in the flues had not passed 
through the furnace, leaving the supply of air 12 pounds per 
pound of dry tan. 

In this experiment the draft was controlled by nearly closing 
the ash pit doors. No smoke came from the chimney. The top 
of oven was covered with tan. 

This was the most successful experiment made on the Crockett 
furnace, and the results indicate that the success was mainly 
owing to the manner of firing, and to the fact the draft was con- 
trolled by the ash pit doors, in place of by the damper in the 
chimney, the effect being to make the area of egress larger than 
the area entrance for the air. The tan on the top of the furnace 
undoubtedly saved some heat. This experiment being the best 




19 



performance of the Crockett, should be compared with the besl 
performance of the Hoyt and Thompson furnaces ai Wilcox and 
Binghamton. If the air in the chimney had not been diluted w ith 
25 percent, of air from the outside, its temperature would have 
been 650°. 

EXPERIMENT MARKED WELLS' (4). 

This experiment was made to determine the effect of reducing 
area of exit for gas. The rate of combustion was the same, the 
manner of firing was the same, the temperature of the furnace 
was nearly the same, and the chimney 10° colder. 

Notwithstanding, the steam generated by one pound of dry tan 
was 5 per cent. less. The area of flues in this experiment was 
reduced until they had some influence on the gas flowing from the 
boiler, and resulted in a small loss of combustible gas. Their w as 
some smoke during this exeriment. 

During the experiment marked Wells' (1) there was an exc< 36 
of steam formed over that required to run tannery. 

During the experiment marked Wells' (3) there was sufficient 
steam formed to carry 60 pounds pressure and run the whole tan- 
nerry, including heating liquors and all the machinery they ever 
ran. The consumption of tan was at the rate of 4 cords in 1 2 
hours, or, allowing 1 cord for banking fires, 5 cords per day. hci un- 
less than one-half of the bark they used for tanning their hides. 

MANNER OF MAKING EXPERIMENTS. 

The experiments were all made in the same general manner as 
follows : 

Tan — The tan was measured in a box at its natural density; 
that is, merely shoveled into the box and "struck" with a 
straight edge. The box was counterbalanced on platform 
scales, and the weight of tan contained in each bos noted in 
the log. After the furnace had been running a tew hours, 
so that the amount of tan required was known, it v. 
arranged to deliver a boxful every 5, L0, T> or 20 minufc 
according as required. The boxes, under these eircumstana 
were dumped at exactly the end of these intervals; thai is, if there 
were required 3 boxes of tan per hour, one would be dumped 
at the even hour, one at 20 minutes past, and one ai 20 minutes 
before, exactly. The object of this arrangemenl was to prevent 
any confusion as to the number of boxes delivered; When, i 
Wilcox, there are used sometimes 20 boxes .in hour, such an ar- 
rangement is found to be necessary. The tall] of the weigh! of 
each box, and the minute at which it was dumped, was kepi bj 

® 



"& 





i<> 




myself and the man who was in charge of the gang of shovelers. 
WaUr in tan — The water in the tan was determined by drying 
several specimens of 200 grammes each, taken from a sample of 
one quart brought from the tannery in a hermetically sealed glass 
jar. The tan was dried by my associate, Prof. J. K. Rees, of 
Columbia College, in an air bath at 110° Centigrade. The method 
of obtaining the sample of one quart was as follows : There was 
provided a tin case with a lid and lock. A double handful of tan 
was taken from each boxful of tan as weighed upon the scale and 
thrown into the tin case. The case was kept locked except when 
opened to receive samples. At the end of the day there would be 
collected in this case from 40 to 200 double handfuls of tan, being 
collected in equal portions from every boxful of tan used. 

At the end of the day the tan in the case was shaken well up 
and then spread out upon a table and divided into equal small 
parts, alternate small parts being taken and the balance rejected. 
The original easeful was thus reduced by successive divisions (one 
half being rejected each time) to one quart, when it was carefully 
placed in the jar, sealed, labeled, and sent to New York by 
express. 

Water — The water pumped into the boiler was all measured in 
casks, the weight contained by the casks, weighed on the same 
scale as the tan, having been originally determined. There were 
generally three tiers of casks, the lower one being connected with 
the pumps and acting as a reservoir, the middle one acting as a 
measuring cask, and the upper one receiving the supply of water 
and being provided with an overflow at the top and a plug in the 
bottom. The middle or measuring cask also had a hole in the 
bottom and a plug. 

The mode of operation was as follows : The man in charge of 
the water would, when the measuring cask was empty, put the 
plug in the bottom and pull out the plug from the upper barrel, the 
water immediately commencing to flow from the upper into the 
measuring cask. When the measuring cask was full, he would put 
the plug in the upper barrel, and after a few seconds, when the 
surface of the water had subsided to the level of the overflow hole, 
would pull out the plug in the measuring barrel and allow the 
water to flow into the lower barrel, whence it would be pumped 
into the boilers. The same precaution was taken to avoid con- 
fusion by emptying barrels at exactly even intervals, as in weigh- 
ing tan. 

Water entrained with steam — This was determined by a special 



2l 



apparatus designed for the purpose and earned around to all the 
tanneries tested. It consisted of a worm, through which a small 
portion of the steam coming from the boiler was passed, expi 
to cold water on the outside. The measurements taken were : 

1. The weight of water coming from worm per hour being the 
sum of the steam and water coming from the boiler into the worm. 

2. The weight of water passing over the outside of the worm, 
which carried away all the heat abstracted from the water and 
steam. 

3. The temperature of the water before and after passing the 
worm, the temperature of the water delivered from the worm, and 
the pressure of the steam in the boiler. 

These three measurements supply all the data necessary to 
determine the amount of water entrained with the steam. 

The weight of water passing the outside of the worm was determ- 
ined by noticing the head of water over an orifice in the bottom 
of the box in which the worm was, necessary to force all the water 
through. The volume of water which would be delivered by this 
orifice for each ^ inch increment of head had been previously 
determined, and was as follows : 




CUBIC FEET OF WATER DELIVERED PEE HOUR FROM ORIFICE IN BOTTOM OF TANK AT VARIOl'9 
HEADS FROM 16 INCHES TO 25 INCHES, AT A TEMPERATURE OP 72 DEGREES F. 



Head 
25 

24% 

24% 

24% 

24 

23% 

23% 

23% 

23 

22% 

22% 

22% 

22 

21% 

21% 



21 

20% 
20% 



Cubic feet water. 

riches 39.60 

riches 22 

uches 02 

nches 38.82 

riches 62 

nches 42 

nches 22 

nches 01 

nches 37.80 

nches GO 

nches 39 

nches 18 

nches 36.98 

nches 77 

nches 55 

nches 34 

nches 13 

nches 35.91 

nches 69 



Head. Cubic feet water. 

20% inches 35.17 

20 inches 26 

19% inches 05 

19% inches 34.82 

19% inches 69 

19 inches 86 

18% inches 13 

18% inches 88.90 

18% inches 

18 inches 46 

17% inches 21 

17% inches 32 



17% inches 
17 inches 



.71 
.60 



16% inches 26 

16% inches 02 

16% indies .11. 7s 

16 inches 



The figure given in the log is the " head of water in tank.'' \\\ 
entering this table with the head, the volume of water correspond- 
ing can be determined." 



*Itis believed that the idea of determining the water entrained with the Bream I y 
condensing a small portion continuously in a worm an. I weighing and measuring all 

quantities, originated with Mr. J. D. Van Buren, Jr. 



?&- 





%% 




Temperatures — The temperatures, when below 600°, were taken 
by a thermometer. Above 600°, they had to be approximated to 
by means of the melting point of metals. Specimens of the 
same piece of metal were used at all furnaces, and the results are 
therefore fairly comparative. 

Method of proceeding — The engineer generally took charge of 
the' firing, and conducted it in the manner he supposed best cal- 
culated to produce the best result. As all of the engineers seemed 
to feel considerable pride in having their furnaces do well, I have 
reason to suppose each did his best. 

Supervision — I was present at the furnace during the whole of 
each experiment, never leaving it for a single instant, and had a 
complete supervision of all operations during the whole time. 

Ashes and refuse — These were determined by raking out the 
fire and commencing with the tan that had been weighed (in 
Stevens' and "Wells' 1), and by weighing the ashes and refuse dry 
at the end of experiment. The ashes were found to be so small a 
percentage, and so much mixed with unconsumed tan, that the 
attempt to measure them was given up after these experiments. 

In all others the fire was left at same condition at end as be- 
ginning, i. e., Thompson and Wilcox furnaces full, and Crockett 
average thickness. 

THOMPSON FURNACES. 

These furnaces are built in some respects as described in the 
patents of Moses Thompson, as interpreted by the court. They 
consist of a series of ovens arranged in pairs, each pair of ovens 
with the boilers attached being complete in itself. The ovens are 
built of fire-brick, generally from 4 to 4| feet in diameter and 
from 10 to 12 feet long. The crowns of the ovens are semicircular, 
and the grates are in the horizontal diameter. 

The ovens are fed with wet tan through two openings in 
the top of each oven. These openings are about one foot in 
diameter, and so placed in the top of the oven as to best distribute 
the tan uniformly over the grate. They are supplied with iron 
covers, but except when starting or burning down the fires these 
covers are not used, as the tan, kept two feet deep all over the fire 
room floor, effectually seals these openings. The tan is fed as 
often as in the judgment of the fireman it is required. 

When about to feed, he first breaks down the layers of bark 
which have dried and baked hard over the top and in the feed 
hole, and then with a bar spreads out the mass of embers and 
ashes left from the tan last fed in, and finally shovels into the 



23 




oven all the bark that will run into the feed holes, and ends 1 
filling all up and tramping clown the bark into the hole, and coven 
the top with about two feet of wet tan as before. 

So far as in the method of construction and operation, I do no! 
understand that the representatives of Thompson make any claims 
to novelty. 

Their peculiar claims are as follows : 

The grates are made of fire brick and are 2| inches wide on top 
and have a space between them \ inch wide, the total area of 
openings between the bars for the admission of air being less than 
20 percent, of the total grate surface, while in the ordinary forme 
of grate for coal it is about 33 per cent. 

The space between the bars (£ inch wide) allows a small amount 
of tan to run through, partly from its own weight, during the 
whole process of combustion, but mostly wliile the fire is being 
stirred preparatory to being fed. The whole amount that runs 
through is, however, a very inconsiderable proportion, and would 
scarcely be felt if it were lost. I do not think it can exceed 10 
per cent, in either of the furnaces experimented on, and was 
probably much less. The amount that runs through, to a certain 
extent, regulates itself. It falls into a second oven, built of fire 
brick, taking the place of the ordinary ash pit. This oven is 
double for each furnace, the dividing wall being necessary to rap- 
port the fire brick grates. In the furnace at Bingham ton thej 
were each 22 inches wide and 12 feet long. All the air that entei B 
the oven through the grate passes through a small register m the 
ash pit door into the ash pit, and may then rise through the grate 
into the furnace, or may pass along under the grate over the glow- 
ing surface of the embers in the ash pit. The amount of air reach 
ing the embers in the back end of the ash pit is aecessarirj small. 
The embers falling through the grate slowly accumulate in the 
ash pit, not consuming as fast as they pass through, until the top 
of the pile of embers touches the bottom of the grate liar and pre- 
vents the falling through of anymore. During the time the. mben 
are accumulating they only fall through \en slowly, perhaps two 
or three a second. 

When the embers are accumulated in the ash pit aearlj up to 
the grate bars, the whole surface of the mass of embers, brick 

work and grate bars hasa very high temperature, perhaps 2,4 I 

The reason for this is, I conceive, not on account of the quantity 
of tan consumed there, or on account of the perfection of the 
combustion, but because the heat radiated from the i mbera U 






34 

■ ^e 

1 



carried away. Only a very small quantity of air circulates 
through the ash pit under these circumstances, and as all the ash 
pits in the group, except the two outside ones, are surrounded by 
others equally hot, but little heat is lost by radiation. 

When, on the other hand, the surface of the embers is six or 
eight inches below the under side of the grate bars, the tempera- 
ture of the gas at the back end, after passing over the whole 
length of the ash pit, is not sufficient to melt lead. 

The other peculiarity of the Thompson furnace, as built at 
Binghamton or Brackneyville, is the contraction and combination 
of the outlets for the products of combustion from each pair of 
ovens. 

The inventor claims that by contracting and combining the flues 
leading from the furnace to the boiler, any combustible gas coming 
from one furnace will be consumed by the excess of oxygen in the 
products of combustion coming from the other, or, in the words of 
Prof. Silhman, " the gases from the two furnaces may mingle 
and consume each other." 

In order that this may take place these three conditions must 
simultaneously exist : 

1. There must be combustible gas in the products of combus- 
tion of one furnace. 

2. There must be an excess of oxygen in the products of com- 
bustion of the other. 

3. There must be a sufficiently high temperature hi the mixed 
gas (about 1,500°). 

There was no provision for the admission of air into the com- 
bustion chamber of either the Thompson furnace at Binghamton 
or Brackneyville other than that which found its way through the 
oven without uniting with the incandescent tan — that is, that 
passed through an oven 10 feet long filled with tan at a tempera- 
ture of nearly 2,000°. If there were any combustion taking place 
in this chamber I judge there must have been some appearance of 
flame there. There was a small hole drilled in the door of the 
chamber of the furnace at Binghamton (Weed's) which allowed an 
observation of the whole interior at any time without opening the 
door. The whole interior was nearly always perfectly clear. 
Occasionally a little flame came out of the oven info the chamber. 

weed's furnace at binghamton. 

The experiment was made on this furnace by allowing the engi- 
neer to take entire charge of the method and quantity of firing, he 




35 /. .-.j" 


proceeding as lie said he had found by Long experience to be the 
best way. 

The tan was brought from the learlns and duui]"'l on the fire 
room floor, where it was kept about two feel thick th<' whole time. 
The fireman fired the oven without any apparent system, tip- 
average number of times each oven was fired being, including 1 »* * 1 1 1 
holes, twice every 3 hours or 8 times during a day of L2 hours. 
Sometimes both feed holes were fed at once in one furnace of the 
pair, sometimes one feed hole hi each was fed, and sometimes both 
feed holes in each furnace during the same hour, but generally one 
feed hole in one oven hi one hour and the opposite feed hole in 
the next oven during the next hour, the feed holes nearest the 
boiler being fed every four hours, and those farthest from the 
boiler every two hours. 

The ash pit doors were arranged so as to expose an area of 
nearly one-third square foot for each oven, or one-sixth square foot 
for each ash pit, and were not changed during the experiment. 
One ash pit was raked out partly, the other being nearly full of 
incandescent embers. 

There was scarcely any smoke issuing at any time from the 
chimney, it being just perceptible occasionally. 

The rate of combustion remained nearly constant during the 
whole day, and was nearly 65-100 pounds of dry tan per hour 
per square foot of heating surface. 

The tan on being fed through the feed holes into the oven imme- 
diately commenced to give off vapor from its surface, and, a n as 

the immediate surface was dried, to underg< > a species oi 
distillation giving off combustible gas. This gas accumulated 
the 'furnace apparently faster than it was carried away, for 
smoke would, just after firing, return into the fire room throu| 
the tan packed into the upper part of the feed hole. Che 
room was continually full of smoke. Part of this came from 
combustion of the tan when heaped around the sheet ironwork ol 
the front connection, and part of it from the destructive dk 
tion of the wet tan on the top of the ovens, the lower Layers 
found perfectly charred, but I am of the opinion that part ea 
from the oven back into the fire room. 

The gas from the furnace, aft, a passing into the combust 
chamber, passed forward under the boilersand returned throo 
the tubes into a sheet iron front connection, thence uito the 
stack. The boilers were unprotected on top and had steam 
drums. 

I* *$ 




26 




The tan on being fed into the furnace immediately spread out 
into a cone, the angle at the vertex being nearly 90 degrees, 
reaching from the feed hole to the grate. 

Just before feeding the surface of the oven would be a bright 
red all over, which would gradually cool down to a very dull red 
in that part of the oven nearest the feed hole last fed. The 
weight of the charge of wet tan fed in was nearly 300 pounds. 
The combustion seemed to take place entirely on the surface 
and to reduce the volume of the cone by equal decrements of 
volume from all parts of the surface, to a very obtuse cone about 
60 inches in diameter and 24 inches high. During the process 
of combustion the oven would grow steadily hotter to the end, 
and would be, when fed again, a bright red heat, probably 
about 1,800°. 

Silver exposed in the combustion chamber was readily melted 
at all times, sometimes, however, a little sooner than at others. 
The shortest time was about 30 seconds and the longest about 3 
minutes required to melt a silver " dime." A piece of silver, 
however, hung on a chain and suspended in the furnace bypass- 
ing the ends of the chain through the two feed holes, the posi- 
tion of the coin being about midway between the feed holes and 
between the grate bars and the crown of the oven, thus being 
exposed to the direct action of the flame in the furnace and of 
the radiant heat from the tan, was not melted, although exposed 
during the whole experiment. This must, I think, have been 
because at that point the products of combustion of the tan 
from one cone were diluted with the air which would afterward 
be partly consumed by the tan of the other cone on its way to 
the chinmey. There was a perceptible variation of the color of 
the brick work of the arch, when the tan in both cones was con- 
suming, from a bright red at the end nearest the boilers to a dull 
red at the end farthest from the boilers. I think a coin exjDosed 
in the oven between the second cone and the combustion cham- 
ber would have been melted as easily as in the combustion 
chamber, although this is only an opinion. The fact that the 
temperature was higher after passing the second cone than 
before shows that there was a greater excess of air in the prod- 
ucts of combustion before passing the second cone than after- 
ward, and suggests the idea that several successive cones of in- 
candescent bark (which would be the result of four or more feed 
holes, as in the Hoyt furnace), might still further reduce the 
excess of ah', and therefore increase the temperature of the gas. 




27 





The time during which distillation only is taking place, thai is, 
before the surface of the cone becomes red, does not exceed five 
minutes, but it is probable that the tan is only dried and coked 
to a small depth during that interval, and that the continued 
distillation goes on from the outer layers of the cone from the 
commencement until near the end. On raking away the outer 
surface of the tan during the early part of the pr» ><■.•«.«;, tin- f 1 • 
green undried tan will be found underneath. 

All brick and ironwork around passages for products of com- 
bustion from oven through combustion chamber were nearly air- 
tight. Only an insensible quantity of air can have leaked into 
the flues and mingled with the gas, en route, until the back con- 
nection is reached. This was of sheet iron and may have leaked 
considerable air, and also the front connection may have leaked 
some air. 

The gases on reaching the back connection had sufficient tem- 
perature to heat a small spot on the cast iron doors to a dull red 
heat in the dark. 

The amount of air found per pound of dry tan in the products 
of combustion was (by means of the velocity of smoke in the 
chimney) 10^ pounds. The relative amounts of carbonic acid 
and free oxygen in the products of combustion by volume, in per 
cent, of the dry gas : 

Carbonic acid 11.1 

Free oxygen 10.6 

The heat developed was (see table), (13-100 being allowed for 
radiation per pound of dry tan), 7^ pounds of water requiring 
6 pounds of air. If the air in excess is 10.G-11.1 of th<' car- 
bonic acid, the air supplied per pound of dry tan would be 
21.7-^11.1X6=11.7, or nearly a coincidence. 

If this air had all passed through the combustion chamb 
the temperature could only have been (calculated Erom the 

Elevation of temperature of 10% pound? of air, 1 pouid of fuel and 1.29 poun 
steam, the air and fuel being supplied at 70 degrees and the Bt< 
degrees by the available heat in the pound of dry tan being 7 1 , l.U ''■<>• 

Elevation of the products of combustion being 10', pounds air, 1 pound fa I 
and 1.22 pounds steam from the temperature of the chimin 
by the addition of the heat abstracted by tbo Bteam and radiation 
4.43-f-.13=4.56 

The temperature of the furnace being sufficieni to mell si] 
readily (2,000°), would seem to show thai an amount ol air 
equivalent to 10 per cent, of the products of c< >m1 iubI ion, or 1 HO 
pounds of air, had leaked in, leaving the pounds of airperpoo 
of dry tan which passed through the furnace 9 1 L0, or nearly 







28 





the same in proportion to the heat developed as was found at 
Wilcox, or 1^ times that actually necessary for perfect combus- 
tion. It must be acknowledged that this furnace was injured by 
10 per cent, of cold air leaking into the flues between the com- 
bustion chamber and the chimney. 

Notwithstanding this excess of air there is an amount of heat 
equivalent to 1 1-10 pounds of steam which was not developed 
by combustion, being about 12 per cent, of the heat in the tan 
or 25 per cent, of the heat realized on the steam in the boilers. 

The cause of the incomplete combustion was probably partly 
due to the small supply of air, for it has been found that in order 
to burn all the combustible gas coming from bituminous coal in 
an ordinary furnace, the products of combustion must be diluted 
with 40 per cent, of their volume of air. In the case of the wet 
tan at Weed's furnace the products of combustion of the tan in 
air were already diluted with 40 per cent, of their volume of 
steam, and therefore in order that the proportion of consumed 
gas and the nitrogen and water diluting it should be the same as 
in the case of bituminous coal, the supply of air must be 1| that 
actually necessary for combustion. 

There is a way in which the performance of the Thompson 
furnace is sometimes injured, and in which many of the earlier 
Thompson ovens that did not succeed were probably injured, 
that is, by a too great contraction of the flue leading from the 
oven to the combustion chamber. The effect is the same as on 
the Crockett furnace at Great Bend. The effect of the contrac- 
tion at Binghamton will be considered further on. 

These outlets were arranged as shown in the plans and had an 
area of 3 6-10 square feet for each pair of ovens, being 1-23 the 
grate surface. The cross section of the tubes in one boiler was 

2 8-10 square feet. The temperature of the gas on leaving the 
furnace was nearly 2,000°, and at the entrance to the tubes 
1,000°. The volumes of gas were then in the ratio of 5 to 3, 
and the area of the passages in the ratio of 4 to 3, indicating 
that the passage from the furnace to the combustion chamber 
might have been enlarged at least 1-4 with benefit to the boiler 
without reference to the combustion. 

THOMPSON FURNACE AT BRACKNEYVILLE. 

This furnace was similar to the one at Binghamton except that 
there were two flue boilers, each 3 feet 9 in diameter and 20 feet 
long, with two flues in each boiler 12 inches in diameter. Only 

3 of the 4 ovens were in use, the fourth being bricked off by a 




89 



brick wall in the opening into the combustion chamber. 1 had 
no means of knowing how nearly air-tight this wall was. 

Ths average rate of combustion was 73-100 pounds of dry tan 
per square foot per hour, but as in one boiler it was 97-100 and 
in the othe r 49-100, the average does not measure the relative 
economy. 

Silver could be melted in the combustion chamber (the one 
connected to the pair of ovens) but could not be introduced into 

the oven. 

The performance of this furnace was in every r< -inula r 

to the one at Binghamton, except that as the rate of combust ion 
was only one-half as much per square foot of grate the oy< n- 
were only fed half as often. There was no system of alternate 
feeding, and no changing of the ash pit doors. 

The furnace was not in as good repair as at Binghamton. 

The pounds of air per pound of dry tan were -found to be 18, 
by the velocity of the smoke in the chimney, and by the ana' 
of gas as before, 17 9-10 pounds. 

Assuming the 18 pounds of air as nearest correct we find : 
the temperature of the furnace, computed as before : 

From thermal equivalent of tan 1 ,320° 

From temperature of chimney and steam I.S-'jO'? 




l,335t 

From which may be computed the proportion the air found in 
the chimney bears to the air passing through the furnace, iu ordei 
that the combustion chamber may have a temperature of 1,800 , 
and the weight of air that passed through furnace : 

Pounds of a'.r per pound dry tan 12 

Ratio of air necessary to air supplied 100 : 1 70 

The weight of air leaking into the flues between the oven and 
the chimney was 6 pounds per pound dry tan. 

HOYT FURNACE AT WILCOX. 

This furnace consists of two pairs of ovens, cadi pair of ovena 
being connected with 3 horizontal rluo boilers. Each oven, with 
its boilers, is entirely independent of the other, each being fur- 
nished with a separate feed pipe, steam pipe, water tank, Bafety 
valve and injector. The only things in common between the two 
ovens are the fire-room and the chimin \ . 

The chimney is of brick, 107 foet high above the grate. 

The ovens are each 6 feet wide and I 6 Eeei long. 

The grates are of iron, the width of the bar being 7 L6 inch a 
and of the space 7-32 inches. 



x 



CO.. 




30 





The ash pits are the entire -width of the grate and entirely 
open in front, no doors being provided. 

The distance from the under side of the grate bars to the 
bottom of the ash pit is 4 feet 9 inches. This great height allows 
a double current of air to form in the ash pit, the cold one enter- 
ing at the front near the bottom, passing toward the back end, 
becoming gradually warmed by the radiant heat from the grate, 
rising and returning close under the grate, part entering through 
the grate to the oven, and the balance finally passing out of the 
ash pit at the front at a temperature of 300°. Under these cir- 
cumstances the temperature of the ash pit is about 200°. 

If the furnace is so far closed as to prevent the return current 
of air, that is, if the opening is reduced from 24 square feet to 
2 of 1 square foot, the temperature of the ash pit rises to about 
that of the Crockett furnace, 500°. 

When the front is open there is a small loss, due to heating 
the air which returns to about 300°. 

There is no contraction of the flue from the oven to the space 
under the boilers, the opening being the full width of the oven. 

There are four feed holes, each one foot in diameter, in each 
oven. The tan is fed in through these holes as it burns down, 
and the holes sealed by wet tan kept all over the floor about two 
feet deep. 

The bark is brought about 250 feet by a conveyor from the 
leaches, and may be delivered at any point on the floor by open- 
ing a suitable shoot. 

This furnace was the most complete in all its appurtenances, 
being of originally the best design and in 1he best condition of 
any experimented upon. The boilers were new and tight, the 
brick work sound, and all parts of the boiler and smoke connec- 
tion protected from loss of heat by radiation. The chimney was 
of brick. 

There were dampers in the flues leading from the boilers to 
the chimney. The cross- section of these flues was 4 square feet 
each. In the case where the most tan was burned the danrper 
was kept wide open, and in the case where the least was burned 
it was kept at an angle of 45° in the pipe, the effect being to 
reduce the area to about 2 square feet. 

The pounds of dry tan burned per hour were respectively 1,000 
and 750, or a proportion of 6-10 and 4-10 square inches to one 
pound of dry tan per hour. This opening was not the con 




31 



trolling section in the first case, although it was in th< id. 

The performance of the furnace during the firsl experimented 
not correspond with the maximum, which might be 25 pel cent. 
more, or 1,250 pounds of dry tan per hour, or "\ of a cord. The 
draught was checked in this experiment by a thick bed of ashes 
which had been accumulating on the grate without being raked 
out for 10 days. During this time the ashes had aecmnulat. 
inches to 12 inches deep. The other furnace had not been raked 
out for 4 days. 

No ashes or embers fell through the grate at any time. The 
ash pits were raked out in expectation that some would collect, 
but were found perfectly clean at the end of the experiment. It 
is customary to rake out the furnace through the 8 doors provided 
every fortnight. If it were required to drive the furnace to it- 
utmost it would be necessary to rake them out every week <// 
least. 

The action, manner of feeding, and appearance of the Hovt 
furnace in both experiments is very similar to the Thompson 
furnace already described, except that the temperature of the 
oven was more nearly uniform, and there never was any smoke 
forced back into the fire room through the feed holes. 

The fires weie watched through the small registers provided 
in each furnace door, and were filled up when burned down. 
They were generally allowed to burn down lower, /. c, farther 
from the crown of the furnace than at Binghamton or Brackney- 
ville, the greater height of the furnace, 6 feet in place of \ .1 feet, 
allowing this. 

In this connection it must be remembered that while the rate 
of combustion per square foot of grate surface was at Weed's 
the same as at Wilcox (2), and therefore the rate of com- 
bustion per square foot of superficial area of the cones of tan 
the same, the actual weight of tan in the furnace undergoing the 
processes of drying and coking was nearly 2! tines as much at 
Wilcox as at Weed's, and therefore the performance of the fur- 
naces, so far as all phenomena regarding the intermitted action 
of the drying and coking are concerned, are qoI comparative. 

There was no smoke coming from the chimney at any time 
during the experiments. 




*The openings of 6-10 and 4-10 square inches for one pound i I dry tan b 
hour are equivalent to 8-10 and 6-10 square incbeB, with a chimi 
having a temperature of 600 degrees inBido an< L 60 i 

Wells'. 





33 



A silver coin exposed in the back end of the oven melted 
nearly as soon as at Weed's, in about 60 seconds. 

Much of the air for combustion came through the registers in 
the furnace doors, for although these registers, except for a few 
seconds when looking at the fire, were kept shut, they were only 
iron casting, and must have leaked considerably through the 
badly fitting joints. I do not consider that the air leaking in 
here did any harm, but acted as efficiently as if it had come 
through the grate. 

When these registers were opened to examine the fire, the 
surface of the heaps of tan appeared to be covered with about 
equal portions of black and red cinders, and would begin to 
scintillate and grow rapidly red when the air from the register 
touched it, showing that at that part of the furnace at least, the 
oxygen in the air surrounding the heaps of tan was reduced 
below the point of dilution necessary to insure a rapid com- 
bustion. 

A considerable amount of heat was lost bj* radiation from the 
oven doors. There were 8 of these doors to each furnace, and 
they all became a dull red in the dark over about 1 square foot 
of their surface, the atmosphere outside being 30°. 

The labor of firing at this furnace was very small, owing to 
the convenient arrangement for delivering the tan on the fire 
room floor. One man fired usually both furnaces and tended to 
the water during the day, thus handling usually 10 cords, or 
40,000 pounds, of wet tan in 12 hours. 

If the temperature of these ovens as actually measured be 
compared with the calculated temperature by the two methods 
as before, taking the air at 10 pounds per pound of dry tan, we 
have the following : 

Wilcox (1) Wilcox (2) 
Temperature of oven computed from the known weight of air and 

the thermal equivalent of the tan 2,000° 2,060° 

Temperature of oven computed from the neat given up hy products 

of comhustion to steam and adding temperature of chimney. . . .2,050° 2,080° 



2,055° 2,070' 




Average 2,060° 

This temperature is a little in excess of that estimated from the 
melting point of silver, showing that no air can have leaked into 
the flues between the oven and the chimney. 

The air for combustion was then 10 pounds per pound of dry 
tan, being 1 40-100, that actually necessary for combustion, or 40 
per cent, of " air in excess," being less than at any other place 



33 




where the combustion was perfect. I think this may be due to 
the long oven and 4 cones of tan, by means of which the air in 
the furnace is intermingled, and each particla broughl in contact 

with surface of tan. 

LEACHED BAKK. 

Wood (and inferentially bark) is said by M. Violet to consist of 
a fibrous substance called "cellulose," which is insoluble in 
water, surrounded by a material which is richer in carbon and 
nydrogen. This encrusting material consists mainly of sugar, 
starch, gum, resin, glucose and tannin. All of these, except the 
resin, are soluble in hot or cold water, and are probably wholly or 
partially extracted in the process of leaching. 

They are all compounds of hydrogen, oxygen and carbon, but 
being rich in oxygen will develop by combustion but a small 
amount of heat. On the other hand, the resin, which is per- 
fectly insoluble in water, and must remain entire in the bark 
after the most thorough leaching, contains no oxygen, and has a 
thermal equivalent of nearly 22 pounds of water evaporated from 
212°, or about three times as much as the soluble constituents. 

It would appear then that the thermal equivalent of leached 
bark must be more than of green or unleached bark. 

The average thermal equivalent of the soluble constituents of 
the bark is 6| pounds of water evaporated from 212 , ami of the 
unleached bark (as has been already determined), S.J, pounds of 
water evaporated from 212°. 

There will be extracted from a cord of unleached bark in the 
process of leaching, if thoroughly done, GOO pounds of soluble 
matter, and the remainder will weigh 1,400 pounds when dried 
at 110° C. 

If the thermal equivalent of a pound of the bark as leached at 
the tanneries in the different experiments, lie calculated on the 
basis that the original equivalent Avas <S.\ pounds, and that a cord 
of leached bark has lost the balance of its actual weight, and 
2,000 pounds of soluble material having an equivalent ol 
pounds, we shall find for the thermal equivah nt of each hark in 
pounds of water evaporated from 212 by one pound of hark dried 
at 110° C. : 

Stevens' 8.9 Wells' (2j 

Wells' (1) 9.0 Wilcox (1) »nd ' 

BracUneyville 8.9 Wells' (:ii 

Weed 8.6 Welk'U) 

This would be the weight of water evaporated or the weight of 
steam formed in the boiler by the combustion of one pound of fca 

3 " — <W 




34 




if the combustion in the oven were perfect, and if the boiler sur- 
face were sufficiently extended to reduce the products of combus- 
tion to the same temperature as the outside air, or about 60 c . 

It will be seen that only about one-half of this amount was 
evaporated in any case, and generally less than one-half. 

There are four principal reasons for this discrepancy : 

1. "Water in the bark. 

2. Imperfect combustion. 

3. Eadiation. 

4. Heat carried away in the chimney gas. 

The first of these is entirely independent of the oven or boilers, 
and if the proportion of water to bark were the same, might be 
neglected in every case without affecting the comjmrison. Unfor- 
tunately the proportion of water varies in every case. The water 
put into the oven with the bark has to be evaporated, and absorbs 
the same amount of heat in being evaporated as though it were 
put into the boiler. 

It also lowers the temperature of the oven, thus injuring the 

effect of the heating surface. 

It also dilutes the air entering the furnace, so that probably the 
wetter bark will require a larger excess of air for equally perfect 

combustion. 

The heat in a pound of dry bark that is available, then, is the 
total heat given above reduced by the heat necessary to evaporate 
the water in the bark, and to superheat it to the temperature of 
the chimney (see table) and will be : 

Stevens' 6.9 Wilcox (1) 6.8 

Weil8'(l) 6.9 Wilcox (2) 6.9 

Brackneyville 7.0 Wells' (3) 6.9 

Weed :....7.0 Wells'(4) 6.9 

Wells'(2) 7-0 

This is the weight of water that might be evaporated from the 
boiler by each pound of dry tan * 

INCOMPLETE COMBUSTION. 

Generally in all cases a portion of the heat, about 5 per cent., 
is lost by incomplete combustion. No analysis of the chimney 
gas has been made in these experiments that will show how per- 
fect the combustion was. It can only be inferred from the 
amount of heat accounted for in all other ways, probably being 




*The injurious effect of a small proportion of water in fuel is much less than is gen- 
erally supposed. A mixture of 100 parts, containing 13 parts of wood and 87 parts of 
water, will develop sufficient sensible heat to raise the products of combustion to the 
temperature necessary for ignition, about 500 degrees. The same is true of a mixture 
containing 7 per cent, of charcoal and 93 per cent, of water. 



J 



3.", 



at least 2| per cent, in the best ca£ ce at 1 

and ninch more in the worst. 

RADIATION. 

This loss depends upon the form, arrangemenl and dim< 

of the furnace and boiler, the absolute amount being in 
proportioned to the surface of brick or stone work exposed \l, 
the furnaces must have suffered considerably from radiation, bul it 
we neglect the heat radiated by the brick work over the o< 
which is utilized in partly drying and heating the tan in all fur- 
naces fed from the top, all the furnaces were injured probably 
nearly alike, Wells' 2, 3 and 4 being injured most by radiation from 
brickwork, and Weed most from radiation from sheet iron work 
in back connection, and Wilcox by radiation from furnace doom 

CHIMNEY GAS. 

The heat carried away in the chimney gas amounts to 30 pel 
cent, in Wells' (1) and 15 per cent in Weed's. 
It depends upon two items, viz. : 

1. The excess of temperature of the chimney gas over the cut- 
side air. 

2. The weight of the gas in comparison with the weight of the 
fuel. 

The nearer the temperature of the gas is to the temperature oi 
the atmosphere, the less heat will be carried off in the gas. It is 
the duty of the boilers to reduce the gas to the temperature of th< 
chimney from the temperature of the furnace. If the chimnies hatn 
the same temperature the boiler* may be considered equally fffii u nt. 
ivhatever may be the extent or arrangement of their surface, provide d 
no heat is lost by radiation, and no cold air leaks into the fine* 
from the outside. 

All the boilers tested were injured by a certain am. -nut of air 
which leaked into the flues from the outside, generally through the 
fissures in the brick work or through the joints in the - 
work. Probably Stevens' and Wells' suffered most from this 
cause. At these furnaces the stone and brick work was old 
full of fissures. During the man\ y< are th< y had been in aa tin- 
alternate contraction and expansion of the walls had forced ou1 
the mortar from the joints. During Borne stages in the combus- 
tion smoke issued from these fissures, showing thai there wi re op< n- 




*Tbe surfaces exposed for radiation were (irou work) : 

Weed, surface bark connection 50 square fee) gat Inside 

Wilcox, surface furnace doore 50 Bquare fe< I koh inside 



t# 




36 



ings through the wall, and that the air must flow in when the 
pressures were reversed. 

Brackneyville was nearly tight in the brick work, as were Weed 
and Wilcox, but all these were injured by air leaking in through 
the sheet iron work around the back connection. 

I have no means of estimating the amount of air leaking in 
through the flues, but should consider that it may have been in- 
sensibly small at Wilcox. 

In addition to the ah- leaking into the flues some air leaked into 
the chimney between the boiler and the thermometer. This air 
had no effect on the economy of the boiler, but only reduced the 
temperature of the chimney and injured the draught. The tem- 
perature of the chimney, as measured by the thermometer, cannot 
be taken as a measure of the efficiency of the boiler surface. In 
Wells' and Stevens' in particular there were large cracks around 
the junction of the smoke stack 'with the boiler. 

The leakage of air into the chimney had no effect upon the 
amount of heat carried away by the chimney gas, the temperature 
being lowered as fast as the weight was increased. 

WATEK ENTRAINED WITH STEAM. 

The measurements taken to determine the water in the steam 
are given in the appendix. The results are as follows : 

Per cent, of water in steam. Pounds per hour. 

Wells' (1) 1A 33 

Brackneyville 7.9 95 

Weed 3.4 188 

Wells' (2) 3.5 55 

Wilcox, superheated ; 24 

The dose approximation of the absolute amount of water car- 
ried from the boiler in the two experiments at Wells' suggests the 
idea that this water was due to some condensation of the steam 
after it had left the water in the boiler as dry steam. 

There was considerable surface exposed to the cold air in every 
case, being generally the surface of the steam drums and pipes, 
and in some cases the tops and ends of the boilers. 

The amount of surface in each case can be approximately com- 
puted from the plans accompanying this report, and was as 
follows : 

"Wells' *0 square feet 

Brackneyville 130 square feet 

Weed's 250 square feet 

Wilcox (to atmosphere at 70 degrees) 60 square feet 

Wilcox (to gas in furnace at 2,000 degrees) 50 square feet 






37 



And therefore the pounds of water entrained with the steam 
each square foot of surface exposed per hour : 

Wells' (2) | 

Wells' (1) ...O.v 

Bracknej ville .» 

Weed's „ : 

A perfectly clean. steam pipe filled with steam at 60 | • 

pressure, and exposed to the still air at 80° temperature will con- 
dense steam at the rate of three-fourths of a pound per square 
foot per hour. 

The close agreement of the weight of water entrained with the 
steam, and the weight of water that must have been condensed bj 
the cold ah on the outside of the pipe, leaves no escape from tin- 
conclusion that the water in the steam was entirely dm U 
tion in every case. 

As far as the ill effect of a certain proportion of water on tin 
steam when used in an engine for heating liquor or other pur- 
poses is concerned, it can make no difference whether the watei 
has been condensed from the steam or whether i< is carried from 
the boiler as water, without ever having been steam at all : l>ut ;i^ 
far as the heat abstracted from the fuel by the steam is concerned, 
it does make a very important difference, the heat abstracted 
from the fuel by the steam being the same whether any of it oral! 
of it is afterward condensed, reaching the engine as all steam, 
partly steam and partly water, or all water. 

The heat abstracted from the fuel in the last case being that 
required to evaporate all the feed water pumped in. 

It is therefore necessary in such experiments to pay particular 
attention to the amount of surface exposed to the cold air. 

TEMPERATURE OF CHIMNEY. 
The temperature of the chimney as sliown by tin-rmometer and 
the temperature of the atmosphere, the difference bein) 
ment of the portion of heat lost. wer< 

2 -i - ^ -z^^z 

a o g 




a - 2 

g '. er 



Temperature of chimnev sap.... 700 680 580 510 120 
Temperature of atmosphere 50° 70° 50° 

Difference 650° 510° 530 c n MO 

PRIMING. 

The priming was there fo re nothing in all of the boilei 
mented on. This agrees with all reliable experiments I hi 






38 



seen, the water primed as shown by the experiment being less than 
the instrument could be relied upon to detect. The weight of 
water pumped in is therefore a measure of the steam formed. 

ABSOLUTE EFFICIENCY. 

The absolute efficiency of all the furnaces, as indicated by the 
experiment, being the heat utilized in the steam compared with 
the available heat in the tan, or the proportion that the steam 
actually evaporated bears to the steam which might be evapo- 
rated by the same tan in a perfect furnace and boiler, no allow- 
ance being made for imperfect combustion, insufficient heating 
surface or radiation, are as follows : 

Stevens' 33.6 Wilcox (1) G8.9 

Wells' (1) 44.5 Wilcox (2) 75.7 

Brackneyville 57.1 Wells' (3) 61.1 

Weed 64.7 Wells' (4) 57.3 

Wells' (2) 45.8 

The only furnaces that are fairly comparable are those at the 
same rate of combustion per square foot of boiler surface. The 
rates of combustion — that is, the pounds of dry tan burned per 
square foot per hour, were : 

Stpvens' 1.61 Wilcox (1) 1.05 

Wells' (1) 0.98 Wilcox (2) 0.79 

Brackneyville 0.73 Welis' (3) ' 0.63 

Wee! 0.67 Wells' (4) 0.63 

Wells' (2) 0.64 

Of these experiments Wells' (1) and Wilcox (1) are at nearly the 
same rate ; also Brackneyville and Wilcox (2) ; also Weed and 
Wells' (3) ; Wells' (2) and (4) and Stevens' being out as experi- 
ments made under exceptional conditions. 

Comparing the experiments together, then, that have the same 
rate of combustion, there results : 

Hoyt. Crockett. 
Pouuds dry tan burned per square foot of heating sur- 
face per hour 1.05 0.98 

Absolute efficiency 0.689 0.445 

Relative efficiency 100. 64. 

For the next lowest rate of combustion : 

Hoyt. Thompson. 
Pounds of dry tan burned per square foot of heating- 
surf ace per hour 0.79 0.73 

Absolute efficiency 0.757 0.571 

Relative efficiency 100. 76. 

For the lowest rate of combustion : 

Thompson. Crockett. 
Pounds dry tan burned per square foot of heating surface 

per hour 0.67 0.63 

Absolute efficiency 0.647 0.611 

Relative efficiency 106. 100. 





39 



Although the experiments at Brackneyville and Wells' I can 
not be compared directly together, the \ are both compared witb 
the same furnace at different rates of combustion, and the result- 
ing ratios maybe compared (thai is, 76 and 64), the final ratio 
being 100 and 118. The final ratios then arc (each furnace being 
at the same rate of combustion) : 

Hoyt 122 

Thompson Ill 

Crockett 1 1 1< i 

These are the actual experimental comparative efficiencies of 
two Thompson, two Hoyt and two Crockett furnaces, furnace bring 
taken in the actual condition found. 

The question now arises, "How much of this difference is due 
to the principle of construction and how much to the superiorities 
or defects of each particular furnace." 

The answer to this question may be very accurately inferred 
from the figures already given in the report. 

The main causes of difference are : 

1. Incomplete combustion. 

2. Dilution of air either passing through fire or leaking into 
flues. 

INCOMPLETE COMBUSTION. 

The table at the end shows the total heat accounted for in 
the six cases where the air passing up the chimney was measured, 
as follows : 

Wells (1). Brack. We d. Wilcox 1 1 . Wi 

Steam 3.0? 4.01 L53 1.61 1.17 

Water in bark 2.28 1.91 1.61 '. I > 

Gas 2.94 2.40 1.33 L.78 1.40 

Water of combustion 0.45 0.45 0.50 0. 16 

Sum of above four quantities... 8.70 8.77 7.97 
Calculated thermal equivalent 
of bark 9.00 8.90 8.G0 

Difference being heat unac- 
counted for from all causes. .0.30 —0.13 68 +0. 

It appears from the above thai the combustion was 
complete in all except Brackneyville and Weed (the discrepai 
between Wilcox (1) and (2) showing the limit of accui 
experiment). 

INCOMPLETE COMBUSTION CAUSED BY I ONTRAI n D I Ll E. 

There is a way in which the contracted opening from th< 
into the flue may act injuriously in the Thompson fun 
ried to excess, and is positively a cause tor the failure of many 







4:0 



of the earlier Thompson ovens, and for the incomplete combus- 
tion of the Weed furnace. 

If the opening from the oven into the combustion chamber is 
as much contracted that it is the controlling section, that is to 
say, if it is so small that the principal resistance offered to the 
flow of the gas from the ash pit door to the chimney top is at 
this point, then a considerable portion of the combustible gas 
will escape unburned. 

The cord of wet tan as fed into the furnace contains : 

Water 2,700 pounds. 

Gas 870 pounds. 

Fixed carbon 600 pounds. 

Ashes 30 pounds. 

If completely burned the products of combustion will be at 
the temperature of the furnace (say 1,800°) and will have the fol- 
lowing volume : 

Sleam 240,000 cubic feet. 

Gas and steam and air 300,000 cubic feet. 

Carbonic acid and air 600.000 cubic feet. 

1,140,000 cubic feet. 

It appears, then, that there must pass through the outlet of the 
furnace 1,140,000 cubic feet for every cord of tan burned. 

At the Weed furnace there was burned in each oven one-eight 
of a cord per hour, and therefore there must have passed through 
each outlet 140,000 cubic feet per hour. 

If the outlet had been the controlling section, it would have 
passed this volume, or 2,300 feet per minute and no more. 

The ovens were fed nearly every hour, and therefore the weight 
of the charge must have been g(4,200)=505 pounds, containing 
a volume of steam and gas that will be generated soon after its 
entrance into the furnace, equal to : 

Steam .' . .30,000 cubic feet. 

Combustible gas 10,000 cubic feet. 

40,000 cubic feet. 

being a volume sufficient to fill all outlet from the furnace and 
completely arrest the inflow of air, during 17 minutes, if the gas 
and steam were completely driven off in this time. 

The loss in this case would be the heat equivalent to all the 
combustible gas, or about 25 per cent. 

The process of completely drying and coking the tan lasts 
during the whole time, from one time of feeding until another, 
but is most rapid during the first ten minutes, and probably nearly 
all the gas generated during the first ten minutes in the Weed 




41 



furnace was lost. The actual loss of heat from incomplet.- com- 
bustion was about 8 per cent., indicating that one-third of the 
gas passed away unconsumed in this way. 

The fact that there was a pressure, or at all events an equili- 
brium of the gas in the furnace over the atmosphere, jus< aftei 
firing, was shown by the fact that the smoke from the tan is 
the feed holes returned into the fire room at this time, and kepi 
it so full of smoke as to be almost unendurable. 

This was not so at Brackneyville or Wilcox. . 

In order that the outlet from the Weed oven should be the 
controlling section it must have an area of less than 3 square 
feet, for the opening into the ash pit that only passed air at GO 
was 2 one square foot. 

The actual area may be computed from Wells' (4), when the 
outlet was reduced until it was the controlling section, and must 
be, in order to be the controlling section, less than 400 square 
inches. The actual area of the outlet was 256 square inches, 
being too small to pass the gas and steam as fast as generate. 1. 
and the air necessary for the combustion. 

EXPEKIMENT ON REDUCTION OF OUTLET. 

An experiment was made marked Wells' (4), in which the out- 
let from the flues was reduced until it began to Bensibly affect 
the draught. The area of the outlet was reduced to -\ Bquare 
feet, and the tan consumed £ of a cord per hour, containing (at 
the temperature of the chimney) : 

Steam 100,000 cubic feel pi rcord 

- Gas and air 120,000 cubic feet per cord 

Carbonic acid and air 240,000 cubic feel pi r cord 

460.000 cubic ord 

being nearly 2,300 cubic feet per minute. The furnace wae 
every 15 minutes, and, therefore, the charge, L-12 of on< i 

containing : 

Steam '. 

Combustible gas 8,000 oubfc 

n 3 >ii i 

or enough to completely fill all passages for i >m fun 

for 4| minutes. If the gas were all driven from the tan during 
this time all passages for egress would be filled, qo air could 
enter, and all combustible gas must be wasted, and th< 
would be, as before, about 25 per cent. 
If the period of drying of tan extended from time of B 






4:2 




until the time of feeding again, and the gas and steam were ex- 
pelled uniformly, the loss would be zero. 

I judge from the appearance of the fire that the time occupied 
by the gas and steam in perfectly leaving the tan was about 10 
minutes, and that therefore the loss was less than 10 per cent. 
The actual loss from experiment was about 6 per cent. 

The controlling section was found to be at the ash pit 100 
square inches, and the section that commenced to affect the 
draft at the chimney 360 square inches, fromVhich I infer that 
in order to perfectly consume the tan in a furnace fed from the 
front, or with two feed holes, the areas of opening for air must 
be, per pound of dry tan burned per hour (with a chimney 80 
feet high and a temperature of 500°) : 

Ash pit ■ 0.20 square inches 

Outlet of furnace 2.50 square inches 

Entrance to chimney 1.00 square inches 

Entrance to flues (when one oven is connected to boiler) 1.50 square inches 

and that an area of the following area per pound of dry tan per 
hour will be the controlling section, and will limit the rate of 
combustion : 

Ash pit 0.20 square inches 

Outlet of furnace 0.90 square inches 

Entrance to chimney 0.50 square inches 

Entrance to flues 0.60 square inches 

In the old Thompson furnace at Wells' there were 4 openings 
from the oven into the combustion chamber, each said to be 18 
inches square — 1,300 square inches. They used to burn 600 
pounds of tan per hour with difficulty. This explains why they 
had so much trouble to keep steam. They need all the steam 
coming from 500 pounds of tan per hour, and if they waste all 
the combustible gas they must burn 1,000 per hour. This would 
be at the rate of 1 3-10 square inch of outlet for every pound of 
dry tan, or nearly the limit of thefurna<e in good weather under 
favorable circumstances. If for any reason the maximum per- 
formance is suspended for a few minutes the tannery must stop 
and wait for steam. This they often had to do. Probably their 
whole difficulty would be overcome by enlarging the outlets from 
the furnace to 2^ square feet each. I have no doubt this may 
be done to advantage in many existing Thompson furnaces. 

At Brackneyville the area of outlet from furnace was lj square 
inches per pound of dry tan per hour, being too small. The 
loss by combustible gas here was 5 per cent, of heat utilized. 

The economy of Weed's furnace would probably be increased 



43 



25 per cent, by either doubling the area of outlet Erom the oven 

or by reducing the consumption. 

The rapidity of drying and coking the tan in the Furnace de- 
pends upon the surface of the tan exposed to the radiant ' 
(being equal to the grate surface in a furnace fed from the Eront, 
and to the entire surface of the cones in the furnace fed t'i 
the top), while the amount of water to be given off depends 
upon the rate of combustion, and the portion of the time occu- 
pied in the drying of the tan upon the thickness of the bed on 
the grate. Thus the water and gas will be given off more uni- 
formly during the whole process of combustion it' the fire ia 
carried on the grate 12 inches thick than 8 inches, and if the 
hight of the cone in a furnace fed from the top is 6 feel than 11 
feet. The hight of the cone being limited by the size <>!' tl. 
oven, it follows that for an oven 6 feet in diameter the areas of 
outlet may be smaller. It is for this reason I judge thai the 
Hoyt furnace at Wilcox was able to burn at the rate of one 
pound of dry tan to 1.0 square inch of flue area, and to 6-10 
square inch of chimney area, both being less than the Limiting 
areas for a furnace 4| feet in diameter, or a Crockett furnao 
without loss, although it will be noticed that the heat accounted 
for in the second experiment is more than in the first, indicating 
better combustion at the slower rate. Also when there are four 
feed holes there is a greater chance of one cone being freshly 
fed and giving off steam and gas all the time. If there were 
cones enough the cross areas of outlet, chimney and flue might 
be redaced to the limiting areas without loss. I think that 
ficient air for combustion of the gases would enter the Tb imp- 
son oven in the portion of the rectangular grate hit uncovi 
by the circular bases of the cones, for th< 
further apart in the Thompson furnace in proportion to the 1 
than in the Hoyt. The portion of the grate Left uncovered, 
covered very thin, would remain or soon become bar< I 
openings fulfill the same part as the holes in the "CrockeM 

The furnace at Binghamton was arrange I 30 thai 
were all connected in pairs, the furnace at Bracknej < Llle 
one pair was connected and on.' single, and the furnace a! W 
cox so that each oven was single. The combustion al WJ<* 
was sensibly perfect, while at Binghamton it wa 
feet There is no escape from the conclusion thai 
the furnaces together was at Leasi of - '<< - ' ' 

be said of the hot ash pit. 




*4S 




44: 



It appears from the figures given in report that the combus- 
tion was more perfect at Brackneyville, and that also the sup- 
ply of air per pound of tan was most : 

Weed. Brackneyvil ! e. 
Percentage of total heat in bark lost by imperfect combustion. . . .9.0 2.4 

Pounds of air supplied per pound of dry tan 9.1 12. 

Per cent, of air in excess of that necessary for combustion 50. 75. 

It would appear from these figures that it was necessary to 
supply 1| as much air to the Thompson furnace as w T as necessa- 
ry for combustion, and only 1 4-10 times as much as was neces- 
sary for combustion to the Hoyt. I believe this is actually the 
case, not because of any of Thompson's patents, but because in 
the Hoyt furnace there are four feed cones, and the air and com- 
bustible gas have a better opportunity to be thoroughly inter- 
mingled than in either of the Thompson furnaces when there 
were only two feed cones ; also because a greater part of the air 
in the Hoyt furnace is admitted directly into the oven above the 
fire, and has an opportunity to mix with the gas and consume it, 
while in the Thompson furnace it must first pass through the fire 
and then consume the gas. It will be very hard to get a suffi- 
cient supply of air to pass through the fire without being taken 
up by the red-hot embers. I doubt very much whether it would 
be possible to have an excess of 75-100 of the air taken up in 
the oven of the Thompson furnace as built at Binghamton — 
that is, without some means of supplying fresh ah' into the 
combustion chamber. At Brackneyville air was supplied to the 
combustion chamber through leaks in the badly-fitting door. A 
few holes in the door of the combustion chamber at Weed's 
would supply the air necessary. 

Assuming, then, that there will be required in a Thompson fur- 
nace with two feed holes 1| as much air as is necessary, or 
12 3-10 pounds per pound of dry tan, and that the air supply in 
the Crockett furnace must be 1 6-10 times as much as in the 
Hoyt, or 16 pounds of air per pound of dry tan, the maximum 
absolute officiency of the three furnaces will be when the chim- 
ney gas is at 500 : , and when the wet tan contains 62 per cent, 
of water : 

Hoyt 82.6 110.8 

Thompson 79.2 106.2 

Crockett 74.6 100.0 

In this comparison each furnace has been taken with the air 
supply actually found by experiment, while from what has been 
said it appears that the Crockett furnace will only need 13 pounds 
of air per pound of dry tan. I have not made a comparison on 




45 




the basis of 13 pounds of air for the Crockett furnace becaus< it 
was not an experimental determination, and maybe open to crit- 
icism. 

Nevertheless, I have no doubt that if each furnace were pro- 
portioned in the best manner, and the walls tight, there would 
only be required 13 pounds of air per pound of drj tan, when 
the relative efficiencies would be : 

Hoyt 105.4 

Thompson 101.2 

Crockett 100.0 

The best and an almost perfect result, has been obtained in a 
furnace having an open backed single oven, with a cool ash pit. 
The results of these experiments go to show that two of Thomp- 
son's claims, namely: the hot ash pit and the reduced outlet 
from the furnaces are absolutely injurious, and that the third, 
i. e., the combination of a pair of ovens, is at most of no value, 
for a practically perfect result can be obtained without the com- 
bination in one oven. 

It has been customary to compare experiments on these fur- 
naces, by adding the water evaporated in the boilers to the wati i 
in the tan, and by dividing the sum for one furnace 1>\ the aum for 
the other, paying no attention to the size of the boilers, the method 
of firing, the state of repair, or to anything but the water evapo- 
rated, and the tan burned. 

The results thus obtained give no idea of the relative merits ol 
the two furnaces, but as this method has been persistently adhered 
to in former reports, such a comparison is made here, with the 
following results : 

The average of all of each kind Thompson. .109 

Crockett. ...llii 

The best furnace of each kind Thompson 

Crockott... 100 

The poorest Crockett with the best Thompson. .Thompson 187 

iketl LOO 

The poorest Thompson with tho best Crockett Thompson '.'7 

Crock.if 100 

It appears that by comparing in this way and selecting • I 
amples, any result from a superiority of 37 per cent, to an inferi- 
ority of 3 per cent, may be obtained for the Thompson, while the 
relative efficiency of the two furnaces as slwwn by the exj 

ment is : 

Thompson 

Crockett 

The results of these experiments indicate thai for a burn 
having a chimney 80 feet high, and discharging the gas al a t- m 

j> " #$ 




46 



perature of 600°, the atmosphere being 60°, and the tan being well 
leached and containing 62 per cent, of water, compared with the 
residue dried at 110- C, as follows : 



CALORIFIC POWER. 



One pound of wet tan will, when perfectly consumed, evaporate 
2 pounds of water from 212°, or 5 pounds from 212° per pound 
of dry tan, being about f of the water that would be evaporated 
by one pound of the dry portion or ordinary pine wood. 




POOREST PERFORMANCE. 

One-third of the heat may be wasted by careless firing or 
inferior design of oven, and that there will be evaporated under 
these circumstances 2^ pounds of water for each pound of the dry 
tan. 

CROSS SECTION OF FLUES. 

That in order to insure perfect combustion, the area of egress 
for the gas from the boiler must exceed that necessary for coal or 
wood, and must be for an oven with two feed holes, or fed from 
the front at least, for each pound of dry tan burned per hour at 
the 

Outlet of oven 2.50 square inches 

Entrance to flues 1.50 square inches 

Entrance to chimney 1.00 square inches 

and that the draught must be controlled at the ash pit door. 

When two ovens are connected to one boiler, or when one oven 
has four feed holes, the areas of egress per pound of dry tan per 
hour may be : 

Entrance to flues 1.00 

Entrance to chimney 0.75 

LEAST SECTION OF FLUES, ETC. 

When the fire is forced to the uttermost, the number of inches 
of sectional area at the various points in the passage of the gas 
from the ash pit to the chimney top will 1 >e : 

Entrance to ash pit 0.20 

Outlet to furnace 0.90 

Entrance to flues 0.60 

Entrance to chimney 0.50 

COMBUSTION PER SQUARE FOOT OF GRATE. 

Under the above circumstances the tan will bum at the rate of 
10^ pounds of dry tan per square foot of grate per hour at least, 
and possibly more. It is, however, favorable to economy to have 
a slow combustion per sq\:are foot of grate surface, not exceeding 




A7 



5 pounds per square foot of grate per hour, and probably* 

slower. 

HEATING SURFACE. 

There will be required in the Crockett furnace wheu burning 
pounds of dry tan per square foot of grate surface per hoi 
feet, and in the Hoyt furnace 1£ feet of heating surface for each 
pound of dry tan burned per horn-, being m the last case about the 
same proportion as would be required for a furnace burning 
or wood to furnish about the same amount of heat. 

Although the heating surface required for coal or wood is the 
same as for tan, the cross section of the flues is required to be 
about double, and the grate surface about four times as much, so 
that if the same boilers which originally could just furnish steam 
with wood or coal were attached to a furnace burning tan the 
chimney would have to be much higher. 

ATR SUPPLY. 

The least air used in any of the experiments wheu the cob bus- 
tion was complete was 10 pounds per pound of dry tan, or an 
excess over that actually necessary of 40 per cent., about the same 
as is found in a coal fire. 

RESULTS OBTAINED. 

That when these proportions are observed the combustion was 
found to be perfect in the Hoyt and Crockett oven, and would un- 
doubtedly be perfect in the Thompson if the ash pit was cleared 
out and the area of outlet at the back of the furnace enlarged, and 
that while it may be the results of the patented furnace ma] 1" come 
with skillful management and design equal to the unpatented, it 
appears that the unpatented furnace is practical^ perfect, and 
that therefore the patented attachments have no value at all. 

THERMAL EQUIVALENT OF BABK. 

The numbers assumed for the thermal equivalent of bark dried 
at 110° C. (unleached 8£, leached 9.00 pounds of water Eroni 212 
are probably comparatively corral. Neverthelt 3S, Erom tl • fact 
that in the two experiments at Wilcox the heat accounted for 
overruns these numbers, while at Wells' 1 1 1 and (2) it r< at ' 
there being no margin for incomplete combustion and radiation. 
I am of the opinion that the thermal equivalent of hemloct bark, 
probably from the extra amount of resin it contains, Is more than 
these numbers, and is at least 9 pounds of water Erom 212 foi thi 
unleached bark dried at 110 C. and ««.[. pounds for the leached 
bark. 






4:8 



The details of the drying of the tan, and also of a very elegant 
experiment for drawing and analyzing the chimney gas, devised 
and executed by my associate, Mr. J. K. Kees, were under his 
especial charge, and are properly the subject of an independent 
report. Very respectfully, 

THEEON SKEEL. 



■w 




APPENDIX. 




SiiiienMion* ot" Oven* ami Boilers. 



1 N. Y. 


Webb'- .Mill- 


Br'kneyville, 

.V V. 


Hindi 
N. V. 


W 




Stevens. 

Crockett. 

Flue. 

Iron. 

74 

60 

400 

2.50 

5.40 

1 : 6.66 
24 : 1 
11 : 1 


Wells. 

i rockett. 

Flue. 

Iron. 

90 

78 

830 

5.54 

5.24 

1 : 16.4 
14 : 1 
33 : 1 


Thompson. 
Flue. 

I- " 

-i 

162 

480 

3.14 

I 90 

1 : 2.9 

.".1 : 1 
33 :1 


Thompt 'ii 
Tabular, 

Bi 

- 
1 - ■ 

29 : 1 
27 : 1 


i 








Hight of chimney above grate, ft . . 




Cross area of flues or tubes, sq, ft. . 


PROPORTIONS. 

Grate surface to heating surface . . . 
Grate surface to cross area tubes. . . 
Grate surface to crossarea chimney 



Statement of Means and Totals of Observations and Meaann menfa. 



Date of Experiment. 



Sept. 



Name of owner of furnace. . . . Stevens 

Number of experiment ] I 

Duration of experiment, hours l: 
Pressure of steam 60 



Sept. I Sept. 



TOTALS. 

Pounds of wet tan consumed. 
Pounds of ashes and refuse. . 

Pounds of combustible 

Pounds of feed water 



I 



20,129 

2114 

19.925 

16,760 



TEMPERATURE. 



Furnace (maximum). 
Furnace (average) 

Atmosphere 

Chimney 

Feed water 

Ash pit 



Per cent, water in wet spent 
tan dried at 110° C 

Percent, ashes and refuse. 

Percent, water in gr'n ground 
bark dried at 110= C 



WEIGHTS. 

Weight cord unleached bark 

Weight cord leached wet tan 
Weight cord leached dry tan, 
Weight cord packed wet tan. 



50 

Tim 

140 

180 545 



61.6 

2.6 



4.44! 

1.710.: 



Wells 
I. 
12 



•j;.-M 
265 

2i;.. M:' 
.'7 12 I 



1,80 

"H 
580 

:,:i 
700 



63.4 
2.7 



2,682 

4,294 

i "i '■ 



l:i." k 
I. 
12 
73 



il I ;i 



1,900 
580 

llll 

1,500 



.Mi. 



•J. .-. : 

1.119 

i ..-i 

5,237 



Sept. 



w. ed 
i 

12 
67 






2.00! 

1,900 

69 

.-,111 

I 'I.-. 

1,500 



55 I 



1'JTll 









, , ■ 



Wells ' 

ii 
12 



! 
II" 



I 

1,571 T 

5 i ■ 



Wilcox 

I 
J i 






• 

70 

700 

II 

70 









W 

II 

7.". 






II 






■ .11- • 
I 



in 


N 


W 










•• 




• 

















t& 




50 



Mean of Observations on Apparatus for »etectlng Water Entrained In Steam. 



Experiment 

Number of hours apparatus was in use 

Mean temperature of injection 

Mean temperature of discharge 

Mean temperature of worm 

Pounds water from worm per hour 

Head of water in tank, inches 

Pressure of steam above atmosphere. 



Wells. 


Brack- 


Weed.1 


Wells. 


a.) 


ney. 


1 


(2.; 


5 


5 


6 


6 


49.4 


57.25 


56.29 


48.8 


99.1 


98 5 


104,61 


73.73 


111 


102 


118.3 


74.9 


99 


91.7 


94.4 


49.8 


19.70 


21.75 


18.3 


19.625 


55 


53 


71 


26. 



Wil- 
cox. 



11 

40.9 

83.44 

92.80 

81.18 

20.125 

69 



Calculated Results From Experiments. 



Name of furnace. 



Number of experiment 



Stevens. 



Perc«ntage of water in tan 

Percentage of solid matter in tan. 

Weight of cord of wet tan 

Weight of dry portion of do 

Weight of insoluble portion do 

Weight of portion lost by boiling.. 

HOURLY QUANTITIES. 



Pounds of wet tan burned 

Pounds of dry tan burned 

Pounds of wet tan per sq.. ft. grate. 
Pounds of dry tan per sq. ft. grate 

Pounds of wet tan persq. ft. heat- 
ing surface 

Pounds of dry tan per sq. ft. heat- 
ing surface 



Pounds of wet tan per sq. ft. cross 
section of flues 

Pounds of dry tan per sq. ft. cross 
section of tlues 



Pounds water evaporated 

Pounds water entrainedwith steam 

ECONOMIC PERFORMANCE- 
POUNDS OF WATER EVAPORATED. 



Per pound wet tan from feed. 
P«r pound dry tan from feed. 



Per pound wet tan from 212° 

Per pound dry tan from 212° 

Pounds water evaporated from212 c 
per sq. ft. heating surface 



I. 

61.5 

38.5 

4,442 

1.710 

1,626 

84 



1,675 
645 



27.9 
10.7 



4.19 
1.61 

67^ 
258 
1,397 



0.833 
2.161 



893 
2.319 



3.79 



Wells. 1 Brack. 



•I- 



63.4 

36.6 

4,294 

1,571.6 

1,478 

93.6 



2,235 
818 

28.7 
10.5 






I 



Weed. 



59.0 

41.0 

4,112 

1,648.9 

1,536 

112.9 



865 
355 



5.4 
' 22 



■I- 



Wells. 



II. 



55.1 I 

44.9 

4,270 

1,917.2 

1,509 

408.2 



62.8 

37.2 

4.225 

1,571.7 

1,424 

147.7 



I 

3,011 I 1,440 
1,352 536 



Per cent, of carbonic acid in dry 
gas by volume 

Per cent, of oxygen in dry gas by I 
volume • • I 

Pounds air per pound dry tun cal- 
culated from velocity of smoke.. 

DISTRIBUTION OF HEAT OF ONE 
POUND OF DKY TAN IN POUNDS OF 
■WATER EVAPORATED FROM 212°. 

Gas passing up chimney heated 
from temperature of atmosphere 
to temperature of chimney 

Water in tan evaporated from 68° 
and superheated to temperature 
of chimney 

Water evaporated in boiler from 
212° 

Waterof combustion, estimated. . 

Sum of above four quantities 
Thermal equivalent of tan ical)... 

Difference, being loss from all 
causes, incomplete combustion, 
radiation, etc 



Arailable heat per pound of dry tan 

Absolute efficiency of furnace and 

boiler 



2.69 
0.98 

404 

147 ! 

2,327 
33 



1.041 
2.809 

1.117 
3.025 

3.36 



7.5 
14.9 

22 



2.94 



2.28 



3.03 
45 



12.4 
5.6 



18.4 
6.8 



1.81 1.50 1.72 
0.73 0.67 0.64 



8.70 
9.1KJ 



030 



6.72 
45.0 



270 

110 

1,203 
95 



1.390 
3.329 

1.680 
4.098 

3.00 



8.9 
13.3 

18 



2.40 



1.91 



4.01 
0.45 



8.77 
8.9 



360 

160 

5,836 
188 



1.938 
4.319 

1.988 
4,529 

2.92 



11.1 
10.6 
10>a 



1.33 



1.61 



4.53 
0.50 



262 



1,547 
55 



1.074 

2.887 



1.192 
3.204 



2.25 



7.97 
8.60 



0.13 
6.99 
57.3 



-0.63 



6.S9 
64.7 



Wilcox. 


Wilcox. 


I. 


II. 


61.2 


61.2 


38.8 


38.8 


4.076 


4,076 


1,581.9 


1,581.9 


1,484 


1,484 


97.9 


97.9 



2,588 
1,004 

13,4 
5.2 



Wells. 



1,942 
754 

10.1 
3.9 






2.72 
105 

401 

157 

4,084 

*s.h.24 c 



1.523 
3 925 

1.790 
4.613 

5.19 



2.04 
0.79 

303 

119 

3,385 
*s.h.24° 



1.750 
4.510 

2.058 
5.304 

4.26 



10 



1.73 



2.19 



4.61 
0.45 



8.98 
9.00 



0.02 



6.81 



10 



1.40 



2.09 

5.31) 
('.45 



III. 

61.5 

385 

4,275 

1,645.9 



1,419 
546 

18.2 
6.1 



1.71 
0.66 

258 

99 

2,048 



1.443 
3.747 

1.605 
4.168 

2.73 



8.2 
14.7 
16 



Wells. 



9.24 
9.00 



024 



6.91 



1.96 



2.07 



4.17 
(1.45 



IV. 

62.3 

37.7 

4,260 

1,606.0 



1,376 
519 

18.0 
6.0 



1.66 
0.63 

550 

207 

1,864 



1.355 
3.594 

1.480 
3 954 

2.50 



8.65 
8.90 



.26 



678 76.7 



6.83 
61.1 



•Super-heated, 24°. 







REMARKS ON EXPERIMENTS. 



(From JVote 3?oo7c.) 

Made an experiment on Crockett furnace Sept 21 and 22. Used 
bark that had been pitched out from leaches 24 hours before, and 
had been draining on ground during that time. Tan was meas- 
ured in box and each box weighed. Furnaces were fired by 
M. A. Stevens in the usual manner, I e., furnace was fired every 
10 minutes nearly, tan being thrown in through both doors and 
whole surface of grate covered 6 inches or 8 inches thick. Con- 
siderable white smoke issued from the stack all the time, but most 
for a few minutes after firing. Temperature of crown of furnace 
near fire bridge (perhaps over half of furnace) was, when the door 
was opened, a dull red ; soon became black after firing. A part 
of unbumed tan dropped through holes in grate into ash pit at a 
bright red heat and slowly consumed there without blaze. The 
temperature of ash pit was found by thermometer held close up 
under grate bars, near back end, 480°-545°. The grates were of 
iron and had been in use 8 years ; were badly warped, and cracks 
were covered over with fragments of iron ; it was through these 
cracks that tan fell into ash pit. There must have been consider- 
able heat lost by radiation from brick work and iron uptake. 
Chimney was part brick and part sheet iron. Sparks could be 
seen in large quantities through hole cut for thermometer, and 
once were seen from top of stack. A great many sparks seemed 
to leave the furnace over bridge wall, and on opening back 
connection doors cinders were found which commenced to 
consume as soon as air Avas admitted. * * * Peed water 
was heated by passing through pipe surrounded by steam ; 
was found to be nearly tight. Temperature of feed L60 
well water 54°. Tally of barrels of water and boxes of 
tan were kept by two persons independently. Water was 
started at three cocks and brought to this poini at end. 
Sample of tan was taken from various parts of heap at 
8 p. m. Zinc was not melted in chimney or ash pit. Copper 

—-———-—- — $ 



Sfy 




was not melted in furnace. Silver was melted in furnace. There 
were many crevasses in brick work around boiler which emitted 
smoke during some portion of time, and which in back connection 
were surrounded by deposit of " coal tar." Dimensions of box 
in which tan was measured : 3 feet 6| inchesX2 feet 3 inchesX 
2 feet 0^ inch ; capacity, 10.2 cubic feet. 



* -x- * -:■:- * 



Made experiment on Crockett furnace at Webb's Mills, recently 
erected, and owned by Mr. Wells. Cone grates in good condition. 
* * * Water measured in barrels, tan measured in boxes. 
Tan had been draining in leach 24 hours before and was pitched 
during experiment ; was wheeled 100 feet in barrows, and then 
dumped 10 feet to fire room floor. * * * During first part of 
experiment damper one-half open and furnace cool ; ash pit door 
8 inches open. During last half fires thicker, I. e., 6 inches over 
crest and 15 inches over hollow of bars ; damper open ; ash pit 
doors 21 inches open ; furnace much hotter ; steam variable, from 
45 to 65 pounds. Stack of sheet iron. Feed water passed through 
heater said and believed to be tight. Pumps worked all time. 
Water supplied to barrels by centrifugal pump. Sides of furnace 
and boiler enclosed by walls of house. Tan apparently wetter than 
at Great Bend and coarser. Boilers apparently good. Gases 
drawn every hour. * * * Engine running all night, blowing 
off occasionally. Water carried during experiment at first gauge, 
but commenced and ended at second gauge. Arches were noticed 
toward the end to be bright red before firing. Seams below the 
surface remaining hot when arches were black after firing. Weight 
of a barrel of water, 315 pounds. Dimensions of box for measur- 
ing tan, 3 feet 2 inchesX^ feet 3| inchesXl foot 11 inches ; 
capacity, 13.7M cubic feet. 



* 



* 




Made experiment on furnace at Binghamton, Sept. 29, 9 a. m. 
till 9 p. m. Ovens were fed^with tan that had drained 36 hours, 
and was pitched continuously during experiment. Tan weighed 




53 



and measured as in other experiments. Water measured in casks. 
The weight of water at 56° necessary to nil cask, 358 pounds. 
Temperature of water when measured during experiment, 205°. 
Had counter on pump. Pump delivered a varying volume of 
water, depending upon the depth of water over the suction pipe. 
Priming determined in the usual way. Air clear, wind south and 
fresh. No smoke from the stack at any time. Never melted 
copper in combustion chamber. Silver melted easily ; silver 
melted in ash pit when held close to surface of embers. Ash pits 
were not cleaned during the experiment except No. 2 oven. Back 
connection doors showed dull red in the dark. Dimensions of box 
for measuring tan, 2 feet 8 inchesX2 feet 10 inchesX2 feet 4£ 
inches ; capacity, 17.8 cubic feet. 

Dampers wide open all the time. No smoke from chimney. 
Time of smoke reaching chimney top from combustion chamber, 
No. 1 and 2 oven, 10 seconds. 




# * * # 




Made experiment on Thompson furnace, Sept. 25-2(5, from 
8 p. m. till 8 a, m. Tan used measured in a box and weighed on 
scales. About one-third of the tan had been over the oven some 
hours (at least twelve) before experiment commenced; balance 
shoveled from the leach about eight hours before. These two 
kinds of tan were mixed by shoveling from one end of the tire 
room to the other before experiment commenced. Whenever 
weight of box of tan in log is marked (*) signifies thai a boxful] had 
been taken from top of oven ; others were taken from heap not on 
top of oven. Ovens were kept buried about three feel deep in wet 
tan during whole experiment. Ash pits were not cleaned out, as 
owners said they could not keep up steam without cinders in 
them. Boilers connected to brick pier supporting chimney 
through sheet iron front connection. Wei tan Laying against this 
connection took fire and burned with flame during whole experi- 
ment. Made sure that i\w blow-off valve was not leakine 1m 
filling it with tan. Silver was melted in one flue Leading from one 
pah- of ovens but not from other. Fires on being examined 
seemed to be equally hot. Furnace was fired everj 2.'. hours, 
nearly, through holes furthest from the door, and every 1 ', hours 






through holes nearest to door. All holes in all furnaces in same 
position were fired at once, i. e., all holes nearest to boiler every 
2% hours, and all holes furthest from boiler every 1^ hours. Fur- 
nace doors had no holes in them and were kept tightly closed and 
luted with fire clay. Ash pit doors were of sheet iron, about 2 
feet square, and were kept so as to expose an opening for the 
passage of air of about 40 square inches to each oven. Glass 
water gauge in chimney showed one-half inch ; did not fall when 
large door to back uptake, 2 square feet, was opened. Tempera- 
ture of stack, 580°. Seems probable that almost all combustion 
took place on surface of cone. Amount consumed in ash pit 
small. Temperature of ash pit 600 : . Water was measured in 
barrels and passed into tank by three men with pails. Tally was 
kept by two men independently. Chimney gases were drawn 
every hour till 4 a. m. Experiment on velocity of air in stack 
was made with coal smoke. Time required to reach chimney top 
from combustion chamber was : 10, 11, 10, 11, 12, Hi, 9, 9, 9, 9, 
9 seconds ; mean, 10.04 seconds. Weight of a barrel of water, 
390 pounds. Flues were swept before experiment commenced. 
Boilers were fed by injector ; no heater ; drip water from injector 
returned to tank. Doors around the furnace and cracks were all 
luted with blue clay and ashes before experiment. Holes above 
the furnace were kept covered with tan, and covers not used. 
Weather rainy during the night and damp in morning. Air, 50° ; 
boiler room, 70°. Dimensions of box for measuring tan : 2 feet 
1\ inchesX2 feet 8g inchesX^ feet 7 j inches ; capacity, 14.69. 

THEBON SKEEL. 




"(^ 



55 







«■ 




56 





5T 





TOP, or STACK SO * 






-1 



&* 



,#.? — ^.rf^-v 



& 




58 



FigS. 1. 



n 



n 




THOMPSON FURNACES. 





The Moses Tliompson Patent for Wet Tan 

Banting Furnaces. 

*. 

v 

(Extracts from Patent, showing Claim and manner of working 

Furnaces.) 

SUBMITTED BY J. S. SCHULTZ, J. B. HOYT AND OTHERS. 

Fig. 1 is a horizontal section of a furnace constructed according 
to my invention. 

Fig. 2 is a vertical section of the same in the line x y of Fig. 1. 

* -v- -X- % M. ^;. 

The main object of my invention is to effect the more economi- 
cal use for fuel of tan bark, bagasse, or other trashy matters in a 
wet state, or very green or wet wood. 

It is also applicable to the burning of fuel of that or other de- 
scriptions in a dry state ; but when the fuel is dry it is much less 
useful, and I do not claim its application thereto. 

The nature of my invention consists in the employment, vn the 
manner hereinafter described, of a series of fire chambers .ar- 
ranged side by side or in any convenient way, to admit of the 
whole series communicating with the same heating flue, which 
said fire chambers are furnished with dampers by which their r< - 
spective communications with the flue and the ash pit m;i\ be 
closed or opened at pleasure. 

This arrangement is for the purpose of enabling the process of 
heating the fuel to an intense degree in a nearly air-tight chamber, 
and then admitting a free supply of air to promote its rapid com- 



fe§>- 





fiO 




bustion, to be conducted without interruption to the operations 
which the heat generated is intended to effect. 

To enable others skilled in the art to make and use my inven- 
tion, I will proceed to describe its construction and operation. 

The furnace shown in the drawings has three fire chambers, A, 
A ', A ' ' . Three is the number shown, as I consider that number in 
most cases to be the best adapted for practical operation. The 
fire chambers are of square but may be of other form with grate 
bottoms, B, B ', B ' ', and arched tops. They are separated by walls 
of non-conducting material, and lined throughout with fire brick. 
Each is provided with a door, C, in front for the purpose of fight- 
ing and tending the fire, with an opening, D, at the top, for the 
purpose of supplying the fuel when it consists of tan bark, saw 
dust, or other material of a similar nature, and with an opening, 
E, at the back, which leads to the flue, F, the opening, E, being 
provided with a damper, K. Each fire chamber has a separate 
ash pit, G, below it, which is furnished with a door, H, to regulate 
the admission of air. 

The flue, F, extends across the back of all three fire chambers, 
and the chimney may be at one end or may be placed in the rear, 
with a flue, I, leading to it from the flue, F. If the furnace is 
used for generating steam, the best place for the boiler will be in 
the flue I, which will be made of proper size to receive and nearly 
surround it. If used for other purposes, any arrangement may 
be made that may be considered best, but the thing to be heated 
ought to be so high as not to require the products of combustion 
to descend on their passage to it. 

The mode of conducting the operations of the furnace is as 
follows : 

Fires being lighted in all the fire chambers, two of the three 
have the doors, H, H, of their ash pits closed, and the dampers, K, 
K, so nearly closed as only to allow a sufficient escape of the gases 
generated by the slow combustion which then goes on to prevent 
explosion. The other fire chamber in the meantime has the 
damper K open, and the door of the ash pit opened far enough to 
admit any quantity of air that may be requisite to promote such 
a degree of combustion in the chamber as may be necessary to 
generate the amount of heat required. The air should be drawn 
in (except when excluded) by natural draft, and if a high stack be 
used, there should be a damper in it to check the draft. 

When the fluel in the ojien chamber is reduced to a desirable 
iegree that chamber is closed and recharged, and another opened 



61 




and supplied with air until the fuel within is reduced, when it is 
closed, recharged, and another opened, each in its turn being 
opened and freely supplied with air to generate and supply the 
requisite amount of heat, while the others are closed and succes- 
sively supplied with fresh wet fuel to heat and|decompose the 
same to such a degree as is desirable before allowing rapid com- 
bustion and escape of the heat to take place. 

Each fire chamber should be supplied successively with fuel at 
proper intervals by any convenient means, either through the hole, 
D, or through the door, C, in front, just before closing the fire 
chamber. 

The principal advantage of a furnace and process of this de- 
scription consists in heating and decomposing the fuel without 
any further loss of heat than is absorbed by the poor conducting 
material of which the furnace is constructed, to such a degree as 
will, when a proper supply of air is admitted, cause the most per- 
fect combustion of the gases and smoke to be effected. This 
could not be effected in a single fire chamber without interruption 
to the proper supply of heat, but when two or more fire chambers 
are employed no interruption takes place, as one furnace is always 
in full operation. Another advantage consists in always holding 
a certain quantity of heat in reserve in the closed chambers, 
which may be immediately brought into action by opening one or 
more of the chambers. 

A similar but inferior result might be produced by having 
several separate grates and ash pits to the same fire chamber, 
each grate charged successively, and its ash pit for a time closed, 
immediately after fresh charging, to exclude the air. 

I have described this in my caveat upon which this application 
is based, but do not use it because of its inferiority in practice, 
although it involves my principle. 

After ample experiments, I have discovered that any results 
which can be produced by the use of dry furl are entirely inferior 
to mine hi proportion to the quantity used, and thai results like 
mine can only be attained by the use of wet fuel, similar to wkal 
I have herein mentioned, fed into an intensely heated chamber. 

Under such circumstances, 1 lie water in the fuel, in the presence 
of the carbonaceous substances in the furnace, will be decom- 
posed, giving its oxygen to the carbonaceous matter, dispensing 
with a draft and its cooling and wasteful influences, and rendering 
the combustion so perfect that no smoke is visible. 
I do not claim the within-described arrangemenl of .1 Beries of 





™ m 

v 

fire chambers to communicate with one common flue, irrespective 
of the purpose for which, and the manner in which, I employ the 
said arrangement. 

But what I do claim as my invention, and desire to secure by 
letters patent, is : 

The combustion, for the purposes of a high degree of heat, of 
bagasse, refuse tan, saw dust, and other refuse substances, or very 
wet and green wood, by the employment of a series of fire cham- 
bers, arranged in any manner substantially as described, to com- 
municate with one flue, when any number of the said chambers 
are nearly closed to the flue and to the admission of air, when 
first charged as described, while the remaining chamber or cham- 
bers is in free communication with the flue, and has a free supply 
of air admitted, and each chamber in its turn is nearly closed, and 
then opened, and has ah - admitted, whereby the heat required is 
furnished by the combustion of the fuel in one or more chambers, 
while the fuel in the other chamber or chambers is being heated 
and decomposed to a desirable degree, as herein set forth, no 
artificial blast being used. 



Note. — The drawings of the real Thompson furnace, as seen on 
page 58, and as described on the three following pages, will suffi- 
ciently indicate the original idea of the patentee. But the claim 
has been construed by the Court to cover the structure on page 
55. For the purposes of this examination the legally construed 
furnace has been assumed to be the true Thompson furnace. 
There are not over three or four real Thompson furnaces — as indi- 
cated by the original drawings and description — in existence, and 
they give very inferior results. J. S. SCHULTZ. 



6?? 

















































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